JP4954975B2 - Periodic structure, method for producing periodic structure, and applied product - Google Patents

Description

  The present invention relates to a periodic structure having a period of about the optical wavelength and a method for manufacturing the same. The present invention also relates to a method for controlling propagation of electromagnetic waves, particularly light using the periodic structure, and applied products.

  In recent years, a two-dimensional or three-dimensional periodic structure having a period of about the wavelength of an electromagnetic wave composed of two or more kinds of media called a photonic crystal (hereinafter abbreviated as “PhC”) propagates the electromagnetic wave. Has attracted attention as a control.

  The concept of the photonic band, which is the basis of PhC, was announced by Non-Patent Document 1, and attracted attention because various interesting properties were presented thereafter.

  The main structures, phenomena, analysis methods, and application examples that are already known are summarized on pages 78 to 137 of Non-Patent Document 2 and Non-Patent Document 3.

  Non-Patent Document 4 and Non-Patent Document 5 describe the coupling between an antisymmetric mode (odd symmetric mode) of self-cloning PhC (hereinafter abbreviated as “AC-PhC”) and an external plane wave.

JP 2001-091701 A JP 2004-279713 A Japanese Patent Laid-Open No. 9-146064 Japanese Patent Laid-Open No. 3-111806 U.S. Pat.No. 3631288 U.S. Pat.No. 5,172,267

Ohtaka, PHYSICAL REVIEW B, Vol.19, No.10, pp.5057-5067, 15 May 1979 Supervised by Shojiro Kawakami, “Photonic crystal technology and its application”, CMC Publishing, 2002 2003 Patent Application Technology Trend Survey Optical Integrated Circuit, March 2004, Japan Patent Office Hiroshi Honma et al., “Coupling of anti-symmetric modes and external plane waves in photonic crystals”, 2004 Fall 65th JSAP Scientific Meeting, September 2004 Hiroshi Honma et al., "Optical attenuator using antisymmetric mode of photonic crystal", IEICE Society Conference, September 2004 Takayuki Kawashima et al., “Fabrication of 2-dimensional photonic crystal polarization separation element and its performance enhancement”, Optoelectronics Study Group of IEICE, OPE99-109, December 1999 Edited by Yasuhiro Ayukawa, “Latest photovoltaic power generation technologies and systems”, CMC Corporation, 2000

  In the situation described above, it is desired to provide a light propagation form, an element that realizes the propagation form, a method for manufacturing the element, and a use form of the element, which have been difficult in the past.

  When a plane wave is incident on an arbitrary position in a thin film optical element at an arbitrary incident angle (or a wide incident angle range), light can be propagated with high efficiency in the plane of the optical element (in the thin film). It was impossible. For example, there are examples of coupling of external plane waves using diffraction gratings, such as optical waveguides and Wood's Anomaly, but a wide angle that is arbitrarily close to the surface with respect to any position in the thin film optical element. When a plane wave is incident in a range, light is not propagated with high efficiency in the plane of the optical element (in the thin film).

  However, if such an optical element is present, the interaction between the medium constituting the thin film and light can be increased.

  If two or more beams propagating in parallel to each other can be obtained from the same coherent light source, it is effective for optical recording and measurement using interference, but difficult with a conventional single optical element. Met.

  The present invention has been made in view of the above circumstances, and provides a method for realizing a light propagation form that has been difficult or impossible in the past and its application.

The first invention is
There is a periodic structure composed of two or more kinds of media having a refractive index greater than 1.2, and there is a combination in which the ratio of the refractive index between the contained media is greater than 1: 1.2, which constitutes a basic unit cell Of the first to third basic translation vectors, a plane including any axis orthogonal to the plane containing the first and second basic translation vectors and parallel to the first basic translation vector and / or the second Refractive index or dielectric constant periodically, characterized in that the dielectric constant or refractive index distribution in the unit structure and / or the basic unit cell is non-mirror symmetric with respect to a plane parallel to the basic translation vector A changing periodic structure.

The second invention is
There is a combination of two or more types of medium having a refractive index greater than 1.2, wherein the ratio of the refractive index between the contained media is greater than 1: 1.2, and the dielectric constant in the unit structure Alternatively, the refractive index distribution and / or the basic unit cell is non-rotationally symmetric and non-inverted symmetric, and the first and second basic translation vectors among the first to third basic translation vectors constituting the basic unit cell are Refraction characterized by being non-mirror symmetric with respect to a plane containing any axis orthogonal to the containing plane and parallel to the first basic translation vector and / or parallel to the second basic translation vector A periodic structure with periodically changing permittivity or dielectric constant.

The third invention is
There is a combination of two or more types of medium having a refractive index greater than 1.2, wherein the ratio of the refractive index between the contained media is greater than 1: 1.2, and the dielectric constant in the unit structure Or a periodic structure having a periodically changing refractive index or dielectric constant, wherein the refractive index distribution and / or the basic unit cell has only translational symmetry.

The fourth invention is:
The periodic structure according to any one of the first to third aspects, wherein the second basic translation vector can take any length that is not zero.

The fifth invention is:
An angle formed by a surface including any two basic translation vectors among the first to third basic translation vectors and the remaining one basic translation vector is larger than 60 degrees and smaller than 90 degrees. To the fourth invention.

The sixth invention is:
The periodic structure is formed by laminating a plurality of thin films, the thin film layer has a periodic concavo-convex structure, and the convex portions in the concavo-convex structure are convex portions having a plurality of distances from the top to the bottom. The periodic structure according to any one of the first to fifth inventions, wherein:

The seventh invention
Any one of the first to sixth inventions, wherein the length of at least one basic translation vector is 100 nm to 1000 nm, and at least one of the media included in the unit structure has a refractive index of 2 or more. The periodic structure described in the above.

The eighth invention
Electromagnetic field relative to a plane containing any axis orthogonal to the plane containing the first and second basic translation vectors and parallel to the first basic translation vector and / or parallel to the second basic translation vector Exhibits a non-mirror-symmetric eigenmode, The periodic structure according to any one of the first to seventh inventions.

The ninth invention
For an electromagnetic field that includes any axis orthogonal to the plane containing the first and second basic translation vectors and is parallel to the first basic translation vector and / or a plane parallel to the second basic translation vector The periodic structure according to any one of the first to seventh aspects, wherein the periodic structure is non-mirror-symmetric and exhibits an eigenmode that is non-rotational symmetric with respect to the axis.

The tenth invention is
A plane and / or a second basic translation vector whose electromagnetic field includes any axis perpendicular to the plane containing the first and second basic translation vectors and parallel to the first basic translation vector regardless of the direction of excitation. Any one of the first to seventh inventions exhibiting an eigenmode that is non-mirror-symmetric with respect to a plane parallel to the axis and has no rotational symmetry three or more times with respect to the axis. The periodic structure described in the above.

The eleventh invention is
An electromagnetic wave beam incident at a predetermined angle on a surface including any two basic translation vectors among the first to third basic translation vectors is propagated in a direction parallel to the surface, or with respect to the surface The periodic structure according to any one of the first to tenth aspects, wherein the periodic structure and the air are propagated at an angle greater than a critical angle.

The twelfth invention
The periodic structure according to any one of the first to eleventh aspects, wherein the incident beam is branched into a plurality of beams propagating in parallel to each other.

The thirteenth invention
The beam propagation direction described in the eleventh invention or the beam branching direction described in the twelfth invention is the direction of the first or second basic translation vector or the first to third basic translation vectors. The periodic structure according to the eleventh or twelfth invention, characterized in that it is a direction in which one basic translation vector remaining on a surface including any two basic translation vectors is projected.

The fourteenth invention is
By changing the incident angle or incident position of the incident beam or the wavelength of the incident beam, the intensity ratio of the two beams propagating in the opposite directions in the plane of the eleventh invention, or the same direction of the twelfth invention is propagated. The periodic structure according to any one of the eleventh to thirteenth inventions, wherein at least one of a beam intensity ratio or a branching interval changes.

The fifteenth invention
Compared to the periodic structure according to any one of the first to seventh inventions, the basic unit cell has the same cross-sectional area or volume, each of which includes the same basic translation vector, and the medium in the unit structure The wavelength corresponding to within ± 30% of the center value of the energy corresponding to the wavelength in which the antisymmetric mode of the periodic unit structure having a mirror-symmetric basic unit cell and unit structure exists A periodic structure having a periodically changing refractive index or dielectric constant, characterized by exhibiting the beam propagation form described in any of the eleventh to fourteenth inventions.

The sixteenth invention is
The periodic structure according to any one of the first to fifteenth inventions, wherein a pn junction or a pin junction exists in a medium in the unit structure of the periodic structure.

The seventeenth invention
The periodic structure according to any one of the first to sixteenth aspects, wherein the medium in the periodic structure contains a transparent conductive material, and the periodic structure has electrical conductivity.

The eighteenth invention
The periodic structure according to any one of the first to seventeenth aspects, wherein the medium in the periodic structure contains a fluid and a solid.

The nineteenth invention
The periodic structure according to any one of the first to eighteenth aspects, wherein a part of the medium in the unit structure contains a nonlinear optical material or a luminescent substance.

The twentieth invention is
The periodic structure according to any one of the first to nineteenth aspects of the invention, and another periodic structure connected to the periodic structure and having a continuous medium and the periodic structure,
A composite period characterized in that a sum of first to third basic translation vectors constituting the periodic structure is different from a sum of first to third basic translation vectors constituting the other periodic structure. Structure.

The twenty-first invention
A composite periodic structure comprising the periodic structure according to any one of the first to nineteenth inventions and a uniform medium connected to the periodic structure.

The twenty-second invention relates to
A method of manufacturing a periodic structure in which at least one of anisotropic deposition and anisotropic etching is used on a substrate on which the concavo-convex shape is formed with one-dimensional periodicity or two-dimensional periodicity. Because
The average incident direction of deposited particles or etched particles to the substrate is not perpendicular to the substrate surface,
The angle formed by the direction in which the incident direction is projected onto the substrate surface and the direction of the periodicity is in the range of 0 degrees to 45 degrees,
A method for manufacturing a periodic structure according to any one of the first to seventh inventions.

The twenty-third invention
The periodic structure or composite periodic structure according to any one of the first to twenty-first aspects of the present invention, a light source, a polarizer, a reflective polarization separation element, a walk-off polarization separation element, a reflection means, a phase plate, a diffraction grating, A device comprising: at least one selected from the group consisting of a scatterer, a spatial light modulator, an electrode, a photoreceptor, and a light receiver.

The twenty-fourth invention is
A parallel beam source, the periodic structure according to any of the eleventh to fourteenth inventions, and a reflective polarization separation element,
A plane including any two basic translation vectors among the first to third basic translation vectors in the periodic structure and the reflective polarization separation element are parallel to each other;
The device according to claim 1, wherein a beam from the parallel beam source is incident on the periodic structure a plurality of times by the reflective polarization separation element.

The twenty-fifth invention
A laser light source, a spatial light modulator, a lens, a photoconductor, and the periodic structure described in the twelfth invention;
By the periodic structure, the beam incident from the laser light source is branched into a plurality of beams propagating in the same direction and parallel to the incident light,
Transmitting or reflecting at least one of the plurality of branched beams by the spatial light modulator;
A device characterized in that a plurality of beams including at least a beam transmitted or reflected by the spatial light modulator are condensed by the lens at the same location on the photoconductor.

  According to the most preferred embodiment of the present invention, it is possible to realize a light propagation form that could not be achieved conventionally. For example, when a plane wave is incident on an arbitrary position in a wide incident angle range, light can be propagated with high efficiency in the plane of the optical element. Further, the incident beam can be split into two parallel beams having substantially the same polarization state or three or more beams.

FIG. 1 is a cross-sectional perspective view of a periodic structure as an example. FIG. 2 is a diagram showing a basic unit cell and a unit structure of the periodic structure shown in FIG. FIG. 2A is a diagram showing a basic unit cell, and FIG. 2B is a diagram showing a unit structure. FIG. 3 shows one type of basic unit cell and unit structure of the periodic structure. FIG. 3A is a diagram showing a basic unit cell, and FIG. 3B is a diagram showing a unit structure. FIG. 4 is a band diagram in which the horizontal axis represents the wavelength of the TE polarized wave incident from the Z direction of the infinite periodic structure having the basic unit lattice shown in FIG. FIG. 5 is a band diagram in which the horizontal axis represents the wavelength of TE polarized light incident from the Z direction of the infinite periodic structure having the basic unit lattice shown in FIG. FIG. 6 is a band diagram in which the horizontal axis represents the wavelength of TE polarized light incident from a direction inclined by 10 degrees from the Z axis and parallel to the ZX plane of the infinite periodic structure having the basic unit cell shown in FIG. is there. FIG. 7 is a band diagram in which the horizontal axis represents the wavelength of the TM polarized wave incident from the Z direction of the periodic structure having an infinite period by the basic unit cell shown in FIG. FIG. 8 is a band diagram in which the horizontal axis represents the wavelength of the TM polarized wave incident from the Z direction of the infinite periodic structure having the basic unit lattice shown in FIG. FIG. 9 is a band diagram in which the horizontal axis represents the wavelength of the TM polarized wave incident from the direction inclined by 10 degrees from the Z axis and parallel to the ZX plane of the infinite periodic structure having the basic unit lattice shown in FIG. is there. FIG. 10 is a diagram showing a self-cloning type two-dimensional photonic crystal and propagation of outgoing light when a parallel beam is vertically incident on the crystal. FIG. 10A is a side view, and FIG. 10B is a front view. FIG. 11 is a diagram showing the propagation of outgoing light when a self-cloning type two-dimensional photonic crystal and a parallel beam are obliquely incident on the crystal with a small incident angle. FIG. 11A is a side view, and FIG. 11B is a front view. FIG. 12 is a diagram showing a self-cloning type two-dimensional photonic crystal and propagation of outgoing light when a parallel beam is vertically incident on the crystal. FIG. 12A is a front view and FIG. 12B is a side view. FIG. 13 is a diagram showing a self-cloning two-dimensional photonic crystal and propagation of outgoing light when a parallel beam is incident on the crystal. FIG. 13A is a front view, and FIG. 13B is a side view. FIG. 14 is a model diagram in which the propagation of light between the “AC-2DPhC” 1001 and the one-dimensional multilayer film 1003 formed on the substrate 1002 shown in FIG. FIG. 15 is a model diagram in which the propagation of light between the “AC-2DPhC” 1401 and the one-dimensional multilayer film 1403 formed on the substrate 1402 shown in FIG. 14 and the air is enlarged. FIG. 16 is a diagram showing a basic unit cell in which basic translation vectors are all orthogonal to each other in a self-cloning photonic crystal and a model of a unit structure in which the medium distribution is biased. FIG. 16 (a) is a diagram showing a basic unit cell, and FIG. 16 (b) is a diagram showing a unit structure. FIG. 17 is a front view showing the direction of the deposited particles or etching particles incident on the substrate and the substrate. FIG. 18 is a top view showing the direction of the deposited particles or etching particles incident on the substrate and the substrate. FIG. 19 is a top view showing the positional relationship between the target and the substrate. FIG. 20 is a front view and a side view showing the positional relationship between the target and the substrate and the incident direction of the deposited particles, etching particles, or etching particles. 20A is a front view, and FIG. 20B is a side view. FIG. 21 is a schematic perspective view showing the substrate 124 shown in FIG. FIG. 22 shows the substrate 124 and the shaping layer 112 shown in FIG. FIG. 23 is an electron micrograph of a cross section in the ZX plane of an actually produced two-dimensional self-cloning photonic crystal (2D-collapsed ACPC). FIG. 24 is a graph of transmission characteristics. FIG. 24A shows characteristics corresponding to the case where the incident beam is a TE polarized wave, and FIG. 24B shows characteristics corresponding to the case where the incident beam is a TM polarized wave. FIG. 25 is a side view showing the basic configuration of the holographic recording apparatus. FIG. 26 is a side view showing the operation during recording. FIG. 27 is a side view showing the operation during reproduction. FIG. 28 shows an HBS used in the second embodiment. FIG. 29 is a diagram showing the polarization compensation type optical integrator and the propagation of incident / exiting light. FIG. 30 is a schematic side view of a photoelectric conversion device based on “2D-collapsed ACPC” made of a-SiC and thin-film polycrystalline silicon. FIG. 31 shows a basic unit cell and unit structure of “2D-collapse ACPC” 3003 shown in FIG. FIG. 31A shows a basic unit cell, and FIG. 31B shows a unit structure. FIG. 32 is a cross-sectional view of a three-dimensional photonic crystal produced using TiO ₂ , SnO ₂ , and iodine solution.

Explanation of symbols

201 First PTV
202 Second PTV
1001 Self-cloning 2D photonic crystal
1004 Incident parallel beam
1005 Output beam
1006 Output beam
1007 Output beam
1008 Output beam
1009 Output beam
1010 Output beam
3107 Area occupied by i-type polycrystalline silicon
3108 Area occupied by i-type polycrystalline silicon
3109 Area occupied by n-type polycrystalline silicon
3110 Area occupied by p-type amorphous silicon carbide
3111 Area occupied by p-type amorphous silicon carbide
3112 Area occupied by p-type amorphous silicon carbide

1. Description of First to Seventh Inventions Hereinafter, the first to seventh inventions will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional perspective view of a periodic structure and peripheral members as an example. A region 101 to a region 111 occupied by a medium having a refractive index n≈1.5, and a region 113 to a region 123 occupied by a medium having a refractive index n≈2.4 shown by hatching form a periodic structure. Reference numeral 124 denotes a substrate, and reference numeral 112 denotes an intermediate layer (shaping layer) between the substrate and the periodic structure. The periodic structure shown in FIG. 1 is a kind of multilayer thin film, and the thicknesses of the region 101 to the region 111 are about 150 nm, and the thickness of the region 113 to the region 123 is about 100 nm.

  FIG. 2 is a diagram showing a basic unit cell (primitive cell, hereinafter abbreviated as “PrC”) and a unit structure (basis, hereinafter abbreviated as “BAS”) of the periodic structure shown in FIG. FIG. 2A is a diagram showing PrC. A first primitive translation vector (hereinafter abbreviated as “PTV”) 201 is 410 nm in length and parallel to the X direction, and the second PTV 202 is It is 251 nm long, has an angle of 86 degrees with respect to the XY plane, and is parallel to the ZX plane. The third PTV is parallel to the Y axis and the length is arbitrary (undefined). Here, the indefinite length indicates that the distribution of the medium in the BAS is uniform in the Y direction, and the length of the PTV cannot be uniquely defined (arbitrary). Reference numerals 203 to 206 denote lattice points. FIG. 2B is a diagram showing the BAS, and is a cross-sectional view taken along a plane parallel to the plane including the first PTV 201 including the midpoint of the third PTV and the second PTV 202. The BAS is composed of a region 207 occupied by a medium of n≈2.4, a region 208 occupied by a medium of n≈1.5, and a region 209 occupied by a medium of n≈1.5 in the visible light range. However, as the periodic structure, the region 208 and the region 209 are continuous, and the BAS substantially consists of two regions. Reference numerals 210, 211, and 212 are vertices of a region of the medium where n≈2.4 (also vertices of a region occupied by the medium where n≈1.5). The periodic structure of PrC and BAS shown in FIG. 2 is a kind of two-dimensional self-cloning photonic crystal (hereinafter abbreviated as “AC-2DPhC”).

  The periodic structure of PrC and BAS shown in FIG. 2 or the periodic structure of PrC and BAS obtained by expanding PrC and BAS shown in FIG. 2 into a three-dimensional periodic structure is for explaining the first to seventh inventions described above. It is. In addition, PrC and BAS obtained by expanding PrC and BAS shown in FIG. 2 into a three-dimensional periodic structure have the same cross-sectional view in the YZ plane as FIG. 2 and the same cross-sectional view in the XY plane as FIG. And BAS.

  The first invention can be explained by PrC and BAS shown in FIG. This is because when the periodic structure of PrC and BAS shown in FIG. 2 selects PTV 201 as the first PTV and PTV having an indefinite length parallel to the Y-axis as the second PTV, A plane including any axis (here, any axis parallel to the Z axis) perpendicular to the plane including the second PTV (here, parallel to the XY plane) and parallel to the second PTV (here, YZ plane) Parallel plane, X is arbitrary) cannot be a mirror plane for any of the refractive index distributions in PrC and BAS, while orthogonal to the plane containing the first and second PTV in PrC A plane including an arbitrary axis and parallel to the first PTV 201 (here, a plane parallel to the ZX plane, Y is arbitrary) is a plane including the midpoint of the length of the second PTV. This is because it becomes a mirror surface for any of the refractive index distributions.

  The second invention can be explained by the periodic structure of PrC and BAS shown in FIG. This is because the refractive index distribution in the BAS is non-rotation symmetric and non-inversion symmetric. Note that PrC has two-fold rotational symmetry. In addition, “the distribution of dielectric constant or refractive index in the unit structure and / or the basic unit cell is non-rotation symmetric or non-inversion symmetric” means that the unit structure can be rotated or inverted with respect to any axis or point. Either the distribution of dielectric constant and refractive index in the inside and the basic unit cell are not the same as the original, or either the distribution of dielectric constant and refractive index in the unit structure or the basic unit cell is not the same as the original Means.

  The third invention can be explained by an example in which the refractive index distribution in the BAS obtained by expanding PrC and BAS shown in FIG. 2 into a three-dimensional periodic structure has no symmetry except translation. Since it is a periodic structure, it naturally has translational symmetry. Note that the description for the refractive index also holds for the dielectric constant ε.

  The fourth invention can be explained by an example in which the second PTV can take any length which is not zero in the PrC and BAS shown in FIG. This is because the medium distribution in the BAS is uniform in the direction of the second PTV and has so-called continuous translational symmetry.

The fifth invention can be described with reference to FIG. This is because the angle between the plane including the first and second PTV shown in FIG. 2A (parallel to the XY plane) and the remaining third PTV is 86 degrees, which is larger than 60 degrees and larger than 90 degrees. Because it is small.
The angle formed by the surface including any two PTVs among the first to third PTVs and the remaining one PTV is preferably larger than 65 degrees and smaller than 85 degrees, more preferably larger than 75 degrees and larger than 85 degrees. Smaller than. When the angle is greater than 65 degrees and smaller than 85 degrees, the electromagnetic waves incident on the surface of the periodic structure, which is a plane parallel to the plane including the first and third PTVs, in the eleventh invention to be described later, This is advantageous because it propagates with a larger ratio in the direction parallel to the plane containing the PTV. Further, when it is greater than 75 degrees and smaller than 85 degrees, the manufacture according to the 22nd invention described later is easy, and the period which is a plane parallel to the plane including the first and third PTVs in the 11th invention described later is provided. This is advantageous because the electromagnetic wave incident on the surface of the structure can be propagated with a larger ratio in a direction parallel to the plane including the first and third PTVs.

The sixth invention can be explained by a periodic structure in which thin films having a plurality of concavo-convex structures as shown in FIG. 1 are laminated in the Z-axis direction. Further, it can be seen from FIG. 2 that the vertex 210 of the medium region of n≈2.4 corresponds to the uppermost portion of the convex portion, and the vertex 211 and the vertex 212 correspond to the lowermost portion of the convex portion. Since the distance between the vertex 210 and the vertex 211 is different from the distance between the vertex 210 and the vertex 212, there are two types (plurality) of distances from the top to the bottom of the convex portion. This form is one of the simplest ways to break the symmetry of BAS. Further, as will be described later, there is the following relationship between the lengths of the first and third PTVs and the wavelength of the electromagnetic wave (light) indicating the propagation characterizing the eleventh or twelfth invention.
The wavelength of the electromagnetic wave (light) indicating propagation characterizing the 11th or 12th invention is a value obtained by multiplying the first PTV by the refractive index of the medium having the largest refractive index contained in the BAS (for example, FIG. 1). In the periodic structure described, the wavelength is about 980 nm or less, preferably a value obtained by multiplying the first PTV by the weighted average of the refractive index of the medium included in the BAS (for example, in the periodic structure described in FIG. 1 Refraction of the medium contained in the BAS with respect to the third PTV and less than the value obtained by multiplying the first PTV by the weighted average of the refractive index of the medium contained in the BAS. It is not more than the value obtained by multiplying the weighted average of the rates and not less than the first PTV (for example, in the periodic structure shown in FIG. 1, the wavelength is not less than 410 nm and not more than 465 nm).

With respect to the seventh invention, as shown in FIG. 2, the first PTV is 410 nm, the second PTV is indefinite (arbitrary), and the third PTV is about 251 nm. The PTV satisfies the condition of a length of 100 nm to 1 μm. In addition, the condition that n≈2.4 of one medium included is also satisfied. Note that the length of the PTV and the refractive index of the medium included have a close correlation with the wavelength of the corresponding electromagnetic wave.
Regarding the length of the at least one PTV, in the eleventh invention described later, the wavelength of the electromagnetic wave incident on the surface of the periodic structure which is a plane parallel to the plane including the first and second PTV is in the ultraviolet region. Is preferably 100 nm to 400 nm, more preferably 150 nm to 350 nm. Similarly, when the wavelength of the electromagnetic wave is in the visible light region, it is preferably 200 nm to 700 nm, more preferably 350 nm to 500 nm. Similarly, when the wavelength of the electromagnetic wave is in the near infrared region, the wavelength is preferably 300 nm to 1000 nm, more preferably 400 nm to 700 nm.

  In addition, PrC shall be defined by selection of general PrC with the best symmetry, except for exceptions.

2. Description of the tenth aspect of the eighth or less, a tenth invention of the eighth, with reference to the exemplary drawings, will be described in detail.

  FIG. 3 shows a kind of PrC and BAS of the periodic structure. FIG. 3A is a diagram showing PrC. The length of the first PTV 301 is 410 nm and parallel to the X direction, and the length of the second PTV 302 is 251 nm and parallel to the Z axis. The third PTV is parallel to the Y axis and the length is arbitrary (undefined). Indefinite length indicates that the distribution of the medium in the BAS is uniform in the Y direction, and the length of the PTV cannot be uniquely defined (arbitrary). Reference numerals 303 to 306 are lattice points.

  FIG. 3B is a diagram showing the BAS, and is a cross-sectional view in a plane parallel to the plane including the first and second PTVs including the midpoint of the third PTV. The BAS includes a region 307 occupied by a medium of n≈2.4, a region 308 occupied by a medium of n≈1.5, and a region 309 occupied by a medium of n≈1.5 in the visible light range. However, as a periodic structure, the region 308 and the region 309 are continuous, and the BAS substantially consists of two regions. The periodic structure of PrC and BAS shown in FIG. 10 is a kind of AC-2DPhC.

  The PrC and BAS shown in FIG. 3 and the PrC and BAS shown in FIG. 2 have the same length of the first and third PTVs, and the volume of the hexahedron formed by PrC is the same. Moreover, the refractive index and the filling rate of all the contained media are the same. On the other hand, PrC and BAS shown in FIG. 3 are mirror-symmetric with respect to a plane including an axis perpendicular to the plane including PTV 301 and PTV 302 and a midpoint of PTV 301, and have two-fold rotational symmetry and inversion symmetry. Have.

  FIG. 4 is a band diagram in which the horizontal axis represents the wavelength of the TE polarized light incident from the Z direction of the infinite periodic structure having PrC shown in FIG. A symmetric mode is represented by a large point (thick line), and an anti-symmetric mode is represented by a small point (thin line). The first band of the antisymmetric mode exists from a wavelength of about 680 nm to a wavelength of about 790 nm, the second band of the antisymmetric mode exists from a wavelength of about 440 nm to a wavelength of about 540 nm, and the third band of the antisymmetric mode is about a wavelength. Present below 430nm. The third band in the antisymmetric mode overlaps with the band in the even symmetric mode.

  FIG. 5 is a band diagram in which the horizontal axis represents the wavelength of the TE polarized light incident from the Z direction of the periodic structure having an infinite period of PrC shown in FIG. FIG. 6 is a band diagram in which the horizontal axis represents the wavelength of TE polarized light incident from a direction inclined by 10 degrees from the Z axis and parallel to the ZX plane of the periodic structure of infinite period of PrC shown in FIG.

  FIG. 6 is a band diagram in which the horizontal axis represents the wavelength of the TM polarized wave incident from the Z direction of the periodic structure having an infinite period of PrC shown in FIG. A symmetric mode is represented by a large point (thick line), and an anti-symmetric mode is represented by a small point (thin line). The first band of the antisymmetric mode exists at a wavelength of about 580 nm to about 720 nm, and the second band of the antisymmetric mode exists at a wavelength range of about 400 nm to about 550 nm. Note that the second band of the antisymmetric mode substantially overlaps the band of the even symmetric mode.

  FIG. 7 is a band diagram in which the horizontal axis represents the wavelength of the TM polarized wave incident from the Z direction of the periodic structure having an infinite period of PrC shown in FIG. FIG. 8 is a band diagram in which the horizontal axis represents the wavelength of the TM polarized wave incident from a direction parallel to the ZX plane of the infinite periodic structure of PrC shown in FIG.

  The eighth invention can be explained by all the bands in the band diagrams shown in FIGS. All the bands in the band diagrams shown in FIGS. 5 and 8 cannot distinguish between a symmetric mode and an antisymmetric mode. This includes an arbitrary axis (an axis parallel to the Z axis in FIG. 2) perpendicular to the plane in which PrC and BAS already contain the first and second PTV (XY plane in FIG. 2), and the second PTV and Because of the non-mirror symmetry with respect to the parallel plane (parallel to the YZ plane), the eigenmode of the electromagnetic field is also non-mirror symmetrical with respect to the plane.

  The ninth invention can be explained by all the bands in the band diagrams shown in FIGS. Similarly, PrC and BAS are already in relation to an arbitrary axis (axis parallel to the Z axis in FIG. 2) perpendicular to the plane including the first and second PTV (XY plane in FIG. 2). Since it is non-rotation symmetric, the eigenmode of the electromagnetic field is also non-rotation symmetric about the axis.

  The tenth invention can be explained by all the bands in the band diagrams shown in FIGS. Similarly, PrC and BAS already include an arbitrary axis (axis parallel to the Z axis in FIG. 2) perpendicular to the plane (XY plane in FIG. 2) including the first and second PTVs, and the second PTV. Is non-mirror-symmetric with respect to a plane parallel to the YZ plane (non-mirror-symmetric with respect to the axis), so that the eigenmode of the electromagnetic field is non-mirrored with respect to the plane regardless of the direction of excitation. It is mirror-symmetric and does not have a rotational symmetry of 3 or more times with respect to the axis.

  In the band diagrams shown in FIGS. 6 and 9, the symmetric mode and the antisymmetric mode cannot be distinguished. The reason is described in Non-Patent Document 4 and Non-Patent Document 5.

  The band diagram shown in FIG. 4 includes an even symmetric mode (Even) band and an antisymmetric mode (Odd) band, and the band diagram shown in FIG. 5 distinguishes between a symmetric mode band and an antisymmetric mode band. However, the two band diagrams are almost the same in the inclination of each band, the folding frequency, the frequency where the band gap exists, and the like. Therefore, the band in FIG. 5 corresponding to the antisymmetric mode band in FIG. 4 is referred to as an antisymmetric like mode band. The band in FIG. 5 corresponding to the even symmetric mode band in FIG. 4 is also referred to as the even symmetric like mode band.

  The fact that the even-symmetric mode and the anti-symmetric mode cannot be distinguished is similar to the case where the beam described in Non-Patent Document 4 is perpendicularly incident and obliquely incident. However, the difference between the band diagram of FIG. 5 compared to the band diagram of FIG. 4 and the band diagram of FIG. 6 compared to the band diagram of FIG. The even symmetric like mode band and the antisymmetric like mode band shown in FIG. 5 corresponding to the symmetric mode and the antisymmetric mode tend to be separated from each other, and the even symmetric mode band and the antisymmetric mode band shown in FIG. FIG. 6 shows that the band structure is remarkably deformed in the vicinity of the frequency in which there is a band gap, but FIG. 5 does not show such a tendency.

  Further, the band edge where the anti-symmetric like mode band exists with respect to the anti-symmetric mode band has a frequency deviation of about 7%. When the angle formed between the first PTV, the surface including the third PTV, and the second PTV in FIG. 2 is further smaller, the difference in frequency is further increased. A deviation of about ± 30% is possible with PrC and BAS similar to FIG.

  Also, the case of comparing the band diagrams of the TM polarization shown in FIGS. 7 to 9 shows almost the same tendency as the case of comparing the band diagrams of the TE polarization shown in FIGS.

3. Description of Eleventh to Fifteenth Inventions The eleventh to fifteenth inventions will be described in detail below with reference to the drawings.

  When the light having a specific wavelength (electromagnetic wave) is incident on the periodic structure (PhC) and / or the device containing the PhC according to the first to tenth inventions, the following phenomena (A) to (R) occur: Arise.

(A) A part of the electromagnetic wave incident on the surface of the periodic structure that is parallel to the surface including the first and second PTVs is parallel to the surface including the first and second PTVs inside the periodic structure. (Corresponding to the eleventh invention).
(B) A part of the electromagnetic wave incident on the surface of the periodic structure which is a plane parallel to the plane including the first and second PTVs becomes diffracted light inside the periodic structure, and the inside of the periodic structure is “first. And / or “the direction of the second PTV” and / or “the direction parallel to the plane including the first and third PTV” and / or “the direction parallel to the plane including the second and third PTV”. To do.
(C) The diffracted light of (B) is totally reflected or reflected at the interface between the periodic structure and the uniform medium, and the rest is transmitted. (Corresponds to the eleventh invention). That is, the periodic structure also has a function as a waveguide.

(D) The diffracted light of (B) that has passed through the interface between the periodic structure and the uniform medium is reflected at the interface between the uniform medium and air (another uniform medium) and is incident on the periodic structure again. To do.
(E) From (B) to (D) above, a plurality of beams traveling in the same traveling direction as the incident beam and in the same direction as the reflected beam are obtained (beam branching, corresponding to the twelfth invention). Further, the plurality of beams have substantially the same polarization state.

(F) The light propagation direction in (A) and the light branching direction in (E) are “the direction of the first PTV and its reverse direction” and / or “the direction of the second PTV and its reverse direction”. Or “the direction in which the third PTV is projected onto the first and second PTV and the opposite direction” (corresponding to the thirteenth invention).
(G) The intensity ratio of the beam propagating in the same direction and the branching interval change depending on the incident angle (corresponding to the fourteenth invention).
(H) The intensity ratio of the beam propagating in the same direction varies depending on the incident position (corresponding to the fourteenth invention).
(I) The branching interval between two beams propagating in the opposite directions within the plane at the same incident angle and incident position varies depending on the wavelength, approximately in proportion to the wavelength. Further, the intensity ratio of the branched light when the incident angle and the incident position are changed also changes (corresponding to the fourteenth invention).

(J) The beam branch interval depends on the size of the in-plane period, the refractive index and wavelength of the medium, the substrate material, and the thickness.
(K) Except for the specific wavelength, the propagation direction of the beam follows normal geometric optics.
(L) The wavelength indicating propagation described in (A) to (J) above is one PTV in which the areas or volumes of PrC and BAS, the periodic structure, and PrC shown in FIG. Is the same as the wavelength of the anti-symmetric mode of the periodic structure of PrC and BAS shown in FIG. (In some cases, there are 10%, 15%, 20%, and 30% deviations) (corresponding to the fifteenth invention).
(M) The product of the size of the first or third PTV and the largest refractive index among the contained media is larger than the longest wavelength at which the propagation from (A) to (K) occurs.
(N) The range in which the plurality of beams propagating in parallel to each other described in (E) are expressed is limited to the range of the multidimensional periodic structure. In addition to the multi-dimensional periodic structure, a plurality of beams propagating in parallel to each other described in (E) are not generated.
(O) The light propagating in the above (A) and (B) leaks out from a place where the period is disturbed such as a defect or a foreign substance on the surface.
(P) Even if light of a wavelength having an antisymmetric mode band is obliquely incident on the PrC and BAS periodic structure shown in FIG. 3, the light propagation of (A) to (J) does not occur.

  Hereinafter, the above-described behavior of light will be described in detail with reference to the drawings. FIG. 3 shows the result of investigating the propagation of a parallel beam of which polarization direction is selected with respect to the periodic structure of PrC and BAS shown in FIG. 2 formed on the substrate.

  FIG. 10 is a diagram showing propagation of emitted light when a parallel beam having a Gaussian intensity distribution by a laser beam with a wavelength of 532 nm is vertically incident on the central part of the “AC-2DPhC” 1001 formed on the substrate. It is. FIG. 10A is a side view, and FIG. 10B is a front view.

  “AC-2DPhC” 1001 is laminated on a fused silica substrate 1002 having a thickness of 0.5 mm and is uniform (one period) in the Y-axis direction. At the same time, a one-dimensional (planar) multilayer film 1003 is laminated on the substrate 1002. In the figure, reference numeral 1004 indicates an incident parallel beam, and reference numerals 1005 to 1014 indicate output beams. Similarly, reference numeral 1015 denotes the incident position and outgoing position of the incident parallel beam 1004 in “AC-2DPhC” 1001, and reference numerals 1016 and 1017 denote the outgoing position of the outgoing beam in “AC-2DPhC” 1001. Reference numeral 1018 represents a defect region existing in the “AC-2DPhC” 1001, and reference numeral 1019 represents a scatterer applied to the surface layer of the one-dimensional multilayer film portion.

  First, as shown in FIG. 10, transmitted light in accordance with Snell's law and two beams having a traveling direction parallel to the transmitted light were confirmed. As for the light propagating to the reflection side, the reflected light according to the law of reflection and two beams whose traveling directions are parallel to the reflected light were confirmed. The beam emission position was limited to the range of the multidimensional periodic structure, and the interval between the three beams propagating in the same direction was 2.0 mm and the same.

  In addition, the same behavior was confirmed in all cases where TE, TM, and linearly polarized waves whose electric field vibration directions were inclined by 45 degrees with respect to the TE polarized wave were inserted. Further, it was confirmed that the output beams 1008, 1009, and 1010 have almost the same polarization state.

  Next, when the incident position of the beam is near the end of the “AC-2DPhC” 1001 in the X direction, four beams are emitted only from the range where the “AC-2DPhC” 1001 exists, and the interval between the four beams is It was confirmed that it was the same as in the case of FIG. It was also confirmed that the intensity ratio of the beam can be changed depending on the incident position, and in particular, the intensity of the output beam 1008 can be made larger than that of the output beam 1009.

  In addition, there is light scattered by the roughness of the AC-2DPhC surface (defect region 1018), and the emission positions of the three outgoing beams are arranged on the end face of the one-dimensional multilayer film 1003 laminated simultaneously with the “AC-2DPhC” 1001. Since the output beam 1011 to the output beam 1014 were output from the position on the extension line, it was confirmed that light propagated in the thin film surface. Furthermore, when the scatterer 1019 was applied to the surface layer of the one-dimensional multilayer film portion, light leakage from the scatterer 1019 was also confirmed.

  Subsequently, when the substrate 1002 and quartz plates of various thicknesses were connected so as to be optically integrated through refractive index matching oil, the distance between the output beams 1008 and 1009 changed.

  FIG. 11 shows the AC-2DPhC 1001 formed on the substrate and a parallel beam having a Gaussian intensity distribution with a laser beam having a wavelength of 532 nm with a small incident angle at the center of the AC-2DPhC 1001. It is a figure which shows the propagation of the emitted light at the time of oblique incidence. The incident surface is parallel to the ZX plane. FIG. 11A is a side view, and FIG. 11B is a front view.

  In the figure, reference numeral 1101 denotes an incident parallel beam, and reference numerals 1102 to 1107 denote output beams. Similarly, reference numeral 1108 denotes the incident position and outgoing position of the incident parallel beam in “AC-2DPhC” 1001, and reference numerals 1109 and 1110 denote the outgoing position of the outgoing beam in “AC-2DPhC” 1001.

  In the example shown in FIG. 11, the branching interval of the light propagating to the transmission side changes depending on the incident angle to the maximum at the time of vertical incidence. The traveling direction of the beam propagating to the reflection side was the same as the direction indicated by the reflection law in geometric optics. Furthermore, it was possible to change the intensity ratio of the beams propagating in the same direction by changing the incident angle on both the transmission side and the reflection side.

  Further, when the incident angle is made larger than in the case of FIG. 11, the number of beams propagating to the transmission side and the reflection side is reduced to two respectively. In addition, when the incident angle is increased, there may be one beam. Furthermore, when the incident direction was changed (rotated around the X axis), the same beam splitting occurred, and the traveling direction of the beam propagating to the reflection side was the same as the direction indicated by the law of reflection in geometric optics. there were. It was also confirmed that the ratio of transmitted light and reflected light can be changed by the incident angle.

  Then, when the wavelength of the incident light was changed, even when a parallel laser beam having a wavelength of 473 nm was incident, the same behavior as the wavelength of 532 nm in FIG. 10 was observed. However, in the case of a wavelength of 473 nm, the beam separation interval at the time of vertical incidence was reduced to 1.4 mm. Furthermore, at a short wavelength of 405 nm, the beam splitting interval at the time of vertical incidence was about 1.0 mm. Furthermore, at a wavelength of 650 nm, it was confirmed that the propagation of the incident parallel beam follows the usual Snell's law and reflection law.

  As described above, the beam branching interval at the same incident angle has a linear function relationship up to a predetermined wavelength. At 532 nm, the ratio between the beam that follows normal geometric optics and the branched light is smaller when TE polarized light is incident than when TM polarized light is incident (more branched light), and at 473 nm it follows normal geometric optics. It was confirmed that the ratio of the beam and the branched light was larger when TE polarized light was incident than when the TM polarized light was incident (small branched light). Branching itself occurs in both TE and TM polarizations, but the intensity of the branched light varies depending on the polarization, and the ratio of the beam and the branched light according to ordinary geometrical optics also depends on the wavelength. The angle formed between the output beam 1011 and the output beam 1013 also changed depending on the wavelength.

  Further, when a parallel laser beam having a beam diameter of 3 mm and a wavelength of 473 nm was incident, the branched beams were overlapped to confirm an interference pattern.

  FIG. 12 shows the AC2DPhC 1201 formed on the substrate 1202 and the output light when a parallel beam having a Gaussian intensity distribution by a laser beam with a wavelength of 532 nm is vertically incident on the AC-2DPhC 1201. It is a figure which shows propagation. FIG. 12A is a side view, and FIG. 12B is a front view.

  In the figure, reference numeral 1203 denotes a planar multilayer film in which “AC-2DPhC” 1201 and a medium are continuous, reference numeral 1204 denotes an incident parallel beam, and reference numerals 1205 to 1215 denote output beams. Reference numeral 1216 denotes the incident position and outgoing position of the incident parallel beam in “AC-2DPhC” 1201, and reference numerals 1217 and 1218 denote the outgoing position of the outgoing beam in “AC-2DPhC” 1201. “AC-2DPhC” 1201 is a part of “AC-2DPhC” 1001 cleaved.

  As shown in FIG. 12, when a part of AC-2DPhC is cleaved and a parallel beam is incident as in FIG. 10, output beams 1211, 1213 and 1215 stronger than output beams 1011 and 1013 shown in FIG. 10 are cleaved. It was confirmed that the output beam 1205 is lower in intensity than the output beam 1005. Similarly, it was confirmed that the intensity of the output beam 1208 was lower than that of the output beam 1008. It was also confirmed that when the incident position was changed in the X direction, the light leakage intensity from the cleaved end face changed, and the intensity ratio of the leakage light beam changed. From this result, it can be seen that the one-dimensional multilayer film part acts as a weak light confinement mechanism for in-plane propagation light. It can also be seen that the space outside the cleaved end face (uniform) also becomes a light confinement mechanism.

Furthermore, using the AC-2DPhC equivalent to Fig. 1 with hydrogenated amorphous silicon (hereinafter “a-Si: H”) and silicon dioxide (hereinafter “SiO ₂ ”), the period in the X direction is 500 nm. When the sum of transmitted light and reflected light was measured for the beam, it was confirmed that the wavelength at which the dip occurred was the same as the wavelength at which the influence of the band of the antisymmetric mode in the vertically grown PhC with the same film configuration exists. Since it is necessary to use a tunable laser, AC-2DPhC equivalent to that shown in FIG. 1 using a-Si: H and SiO ₂ was used.

  FIG. 13 is a diagram showing propagation of emitted light when a parallel beam having a Gaussian intensity distribution by a laser beam having a wavelength of 532 nm is vertically incident on the “AC-2DPhC” 1201 formed on the substrate 1202 shown in FIG. It is. FIG. 13A is a front view, and FIG. 13B is a side view.

In the figure, reference numeral 1301 represents an incident parallel beam, reference numerals 1302 to 1305 represent light propagating in the thin film plane, and reference numerals 1306 to 1308 represent output beams. FIG. 13 shows only characteristic light propagation. Attempts to enter light from the cleaved end face as shown in FIG. 13 confirmed the following.
First, light propagates in the plane of the thin film.
Second, it reflects at the boundary between AC-2DPhC and the one-dimensional multilayer part.
Third, light leaks in the Z direction.

  In addition, it is similar to PrC and BAS shown in Fig. 2. AC-2DPhC made of PrC and BAS with the first PTV of 350nm is formed on a 0.5mm thick fused quartz substrate to split light at normal incidence. As a result, a separation interval of 1.7 mm was confirmed at a wavelength of 405 nm, but no branching was confirmed at any of the wavelengths of 473 nm, 532 nm, and 660 nm.

The light propagation shown in FIGS. 10 to 13 will be described below with reference to the drawings.
FIG. 14 is a model diagram in which the propagation of light between the “AC-2DPhC” 1001 and the one-dimensional multilayer film 1003 formed on the substrate 1002 shown in FIG. In the figure, reference numeral 1401 denotes AC-2DPhC, reference numeral 1402 denotes a quartz substrate, reference numeral 1403 denotes a one-dimensional multilayer film, reference numeral 1404 denotes incident light, and reference numerals 1405 to 1423 denote light rays.

Rays 1404 incident from the air are the first-order diffracted lights 1405 to 1408 inside the “AC-2DPhC1401”, rays 1409 according to Snell's law, rays 1411 to 1412 propagating in parallel with the film of “AC-2DPhC” 1401, not shown The reflected light is branched.
The light beam 1405 that is the first-order diffracted light is totally reflected at the interface between “AC-2DPhC” 1401 and air, and then enters the interface between “AC-2DPhC” 1401 and the substrate 1402. At this interface, the light is branched into reflected light and transmitted light 1416.
Similarly, a light beam 1406, which is first-order diffracted light, enters the interface between “AC-2DPhC” 1401 and the substrate 1402, and is branched into a reflected light beam 1414 and a transmitted light beam 1415.
Similarly, the first-order diffracted light ray 1407 is totally reflected at the interface between “AC-2DPhC” 1401 and air, and then enters the interface between “AC-2DPhC” 1401 and the one-dimensional multilayer film 1403. At this interface, the light is branched into reflected light 1419 and transmitted light 1420.
The light beam 1412 propagating parallel to the film of “AC-2DPhC” 1401 (in the direction parallel to the X axis) is incident on the interface between “AC-2DPhC” 1401 and the one-dimensional multilayer film 1403, and a part thereof is transmitted. If the output of the light beam 1415 is not desirable, the output can be reduced by the following method. The effective refractive index of AC-2DPhC is increased.
-Use a metal material for the substrate. Alternatively, a metal layer is interposed between the substrate and the periodic structure.
-A material having a low refractive index is used as the substrate.

FIG. 15 is a model diagram in which the propagation of light between the “AC-2DPhC” 1401 and the one-dimensional multilayer film 1403 formed on the substrate 1402 shown in FIG. 14 and the air is enlarged. In the figure, reference numerals 1501 to 1502, 1504 to 1509, and 1511 denote light rays, reference numeral 1503 denotes an interface between “AC-2DPhC” 1401 and the substrate 1402, and reference numeral 1510 denotes an interface between the substrate 1402 and the one-dimensional multilayer film 1403.
The light beam 1415 transmitted through the interface between the “AC-2DPhC” 1401 and the substrate 1402 enters the interface between the substrate 1402 and the air and is totally reflected. Then, the light again enters the interface between “AC-2DPhC” 1401 and the substrate 1402, and part of the light is transmitted into “AC-2DPhC” 1401 to generate light rays 1504 and 1505 in accordance with reciprocity requirements. This is the process of generating the branched light.
On the other hand, the light ray 1423 transmitted through the interface between “AC-2DPhC” 1401 and the substrate 1402 enters the interface between the substrate 1402 and the air and is totally reflected. Next, the light enters the interface between the one-dimensional multilayer film 1403 and the substrate 1402 and is totally reflected. Therefore, the light ray 1423 is confined in the substrate 1402.

Hereinafter, the relationship between the wavelength structure of the light propagation and the band structure will be described.
From the wavelength dependence of the light propagation described above, in-plane propagation or the like occurs in the second band of the antisymmetric like mode of FIG. 5 corresponding to the second band of the antisymmetric mode of FIG. In the first band of the antisymmetric like mode in FIG. 5 corresponding to the first band of the nominal mode, the same propagation as that of the bulk plate by the homogeneous medium is generated. In FIG. 5, the band structure near the wavelength where the first band of antisymmetric like mode exists is the same as the band structure near the wavelength where the first band of antisymmetric mode exists in FIG. Since the band structure in the vicinity of the wavelength where the first band of the mode exists is largely deviated from the band structure in the vicinity of the wavelength where the second band of the anti-symmetric mode of vertical growth exists, the configuration of FIG. It is concluded that light propagation described below is performed at a wavelength where the second band or a higher-order antisymmetric like mode band exists.

Differences between the above-described light propagation and a conventional diffraction grating will be described.
In conventional diffraction gratings, a phenomenon is known in which diffracted light satisfying the condition of | sinθ |> 1 (θ is a diffraction angle) is localized as near-field light on the surface of the diffraction grating (interface between the diffraction grating and air). .
The present invention is different in that it propagates not in the interface but in the PhC as propagating light.

  FIG. 16 is a diagram showing a model of BAS in which the distribution of the medium and the PrC in which the PTVs in AC-PhC are all orthogonal to each other are biased. FIG. 16A is a diagram showing PrC. The first PTV 1601 is parallel to the X direction and has a length of 410 nm, and the second PTV 1602 is parallel to the Z direction and has a length of 250 nm. The third PTV is parallel to the Y axis and the length is arbitrary (undefined). Reference numerals 1603 to 1606 denote lattice points. FIG. 16B is a view showing the BAS, and is a cross-sectional view taken along a plane parallel to the ZX plane. The BAS includes a region 1607 occupied by a medium of n≈2.4, a region 1608 and a region 1609 occupied by a medium of n≈1.5. However, as a periodic structure, the region 1608 and the region 1609 are continuous, and the BAS substantially consists of two regions.

  The periodic structure corresponding to the first to tenth inventions is not limited to the periodic structure of PrC and BAS shown in FIG. In general, the periodic structure obtained by three-dimensionally expanding PrC and BAS shown in FIG. 16 or PrC and BAS shown in FIG. 16 is also a first to tenth periodic structure. When all the PTVs are orthogonal to each other, the corresponding periodic structure is limited to the case where the medium distribution is biased by BAS. The band structure of the periodic structure of PrC and BAS shown in FIG. 16 is similar to the band structure of the periodic structure of PrC and BAS shown in FIG.

  Here, it supplements about the difference of PrC and BAS of the crystal | crystallization by the periodic arrangement of PhC and an atom. As shown above, PhC has a large shape of PrC and a large degree of freedom of BAS. Such a feature can be said to be a point that differs greatly between crystals and PhC due to the periodic arrangement of atoms. A crystal having a periodic arrangement of atoms with respect to PrC basically has a three-dimensional structure, and it is difficult to form a two-dimensional periodic structure like PhC, and the same applies to the shape of PrC.

  BAS is limited by the electron trajectory in crystals with a periodic arrangement of atoms, whereas in PhC, the constituent medium itself retains its shape, so there is basically no limitation as long as the manufacturing process is satisfied.

  In addition, as a difference in appearance of the periodic structure, the periodic structure showing the light propagation has an uneven appearance similar to the play-of-color effect seen in gem opals. The periodic structure described in Non-Patent Document 4 had a uniform appearance (similar to translucent colored glass) although it had a color reflecting the transmission / reflection spectrum.

  Up to this point, the special characteristics of electromagnetic wave propagation of the periodic structures according to the eleventh to fifteenth inventions have also been clarified. Therefore, the light propagations (A) to (J) are collectively referred to as H-type propagation. Also, when referring to individual items in H-type propagation, for example, when referring to (A), it is abbreviated as H-type propagation (A).

  Further, the following assistive technology may be added to the first to fifteenth inventions. As already described, in the periodic structure according to the first to seventh inventions, the light propagation described in the H-type propagation (A) to the H-type propagation (D) occurs. As shown in (L), there is a close relationship with the antisymmetric mode of a similar structure having a mirror surface, and controlling the wavelength at which the band of the antisymmetric mode exists is the H-type propagation (A) It becomes a means to control the wavelength at which light propagation described in ~ H type propagation (D) occurs.

In response to this, a “wavelength band expansion method in which an antisymmetric mode band exists” was examined in PrC and PrC by BAS equivalent to FIG. It is already known that the following two points are dominant in the wavelength in which the band of the antisymmetric mode exists, and the influence of other parameters in PrC is small (see Non-Patent Document 6).
(1) The length of the PTV having an angle that is orthogonal to or close to the incident direction (in AC-PhC, the period of irregularities formed on the substrate)
(2) Refractive index and filling ratio of medium used (effective refractive index)

  Based on the above, a simulation was performed. As a result, a periodic structure having a refractive index distribution in PrC or BAS having a complicated structure is generally advantageous for extending the wavelength band in which an antisymmetric mode band exists. all right.

Hereinafter, particularly effective methods for expanding the wavelength band will be listed with reference to the drawings.
As a first effective method, three-dimensional PhC is used. As the number of existence of the direction having the discrete translational symmetry and the size of the period increases, the wavelength at which the band of the antisymmetric mode exists increases, so that the three-dimensional PhC is more advantageous than the two-dimensional PhC. In particular, it is desirable that the lengths of the PTV are different from each other.

  As a second effective method, BAS containing a medium having three or more kinds of refractive indexes is used. This means can be realized by using three or more media to be used and appropriately setting the manufacturing conditions.

  As a third effective method, BAS in which the modulation of the refractive index exists twice or more in the light traveling direction is used.

  For example, if the regions 114, 116, 118, 120, and 122 in FIG. 1 are changed to a medium of n = 3.4, the refractive index modulation exists twice. Moreover, since it is PrC and BAS of AC-PhC, it can easily cope with the first to tenth inventions.

  Or, for example, if the thickness of regions 114, 116, 118, 120, 122 in FIG. 1 is changed to a thickness that is sufficiently different from the thickness of region 115, there will be two index modulations. .

  As a fourth effective method, the PrC parameters are optimized so that the photonic band gap is narrow, the band is folded back, and the group velocity of light in the antisymmetric mode band is reduced.

  It should be noted that the above-described “method of extending a wavelength band in which an antisymmetric mode band exists” can be used not only alone but also in combination. Conversely, when it is desirable that the wavelength band where the antisymmetric mode band exists is narrow, such as when H-type propagation (E) is desired to occur only at a specific wavelength, the above means may be reversed.

4). Description of Sixteenth to Nineteenth Invention Hereinafter, the sixteenth to nineteenth invention will be described in detail with reference to the drawings.

  With respect to the sixteenth invention, for example, in FIG. 2, silicon (hereinafter referred to as Si) is used instead of the medium of n≈2.4 that occupies the region 207, and silicon carbide is replaced with the medium of n≈1.5 that occupies the region 208 and the region 209. This can be explained by an example using a cutting tool (hereinafter referred to as SiC, p-type semiconductor). If an intrinsic semiconductor layer (i layer) and an n-type semiconductor layer (n layer) are formed on the Si, a pin junction can be formed. Since the refractive index of the i layer and the n layer in the Si is almost the same, it behaves as a periodic structure with two media for light.

With respect to the seventeenth invention, for example, in FIG. 2, Si is used instead of the medium of n≈2.4 occupying the region 207, and tin oxide (hereinafter referred to as SnO) which is a transparent conductor instead of the medium of n≈1.5 occupying the region 208 _{2 is} an n-type semiconductor), SiC is used instead of the medium of n≈1.5 occupying the region 209, and an intrinsic semiconductor layer (i layer) and an n-type semiconductor layer (n layer) are formed on the Si. Can be explained by The periodic structure in this case has electrical conductivity in the Z direction. Since the refractive indexes of SiC and SnO ₂ are substantially the same, they behave as a periodic structure with two media for light.

  The eighteenth aspect of the invention can be explained by an example in which one medium is a fluid (gas, liquid) and the other medium is a solid among the medium of the periodic structure showing H-type propagation. The fluid is air or liquid, and the fluid can be moved in and out of the periodic structure, and the wavelength at which the H-type propagation occurs and the branching interval of the H-type propagation (E) are changed by replacing the fluid. be able to.

  The nineteenth invention can be explained by an example using either a nonlinear optical material or a luminescent substance as a medium having a refractive index n≈1.5 or a medium having a refractive index n≈2.4 in FIG. H-type propagation (A) to (D) is the action of confining light in the periodic structure. By confining the light, the electric field strength in the periodic structure increases, and the interaction between the medium and the light can be increased as compared with the homogeneous medium. That is, if the constituent medium of the periodic structure has an optical polarizability having nonlinearity, the efficiency of the nonlinear optical effect can be increased. Furthermore, if the constituent medium of the periodic structure includes a light-absorbing substance, the absorption efficiency can be increased. In the periodic structure, since the light intensity distribution is concentrated on the high refractive index medium, the nonlinear optical material, the luminescent substance, and the optical amplifying substance are combined with the nonlinear optical material, the luminescent substance, and the optical amplification. It is desirable that the refractive index be lower than that of the active substance.

5. Description of the 20th and 21st Inventions Hereinafter, the 20th and 21st inventions will be described in detail with reference to the drawings.

As described above, the peripheral structure of the periodic structure is also a means for controlling the propagation of light. As the peripheral structure of the effective periodic structure, there are the following three types.
(A) Heterojunction of periodic structures having different PrC lengths, PrC directions, and dimensionality. That is, the periodic structures having different sums of PTVs, so-called synthetic vectors, are joined. It is desirable that the constituent media in the periodic structures to be joined at this time are the same, and the constituent media of the same type in the periodic structures are continuous (corresponding to the twentieth invention).
(B) A structure in which the end face of the periodic structure is connected to a uniform medium (corresponding to the twenty-first invention).
(C) A structure in which PhCs having different periods and medium configurations are connected in series in the direction of the third PTV.

  The twentieth invention can be explained by, for example, a combination of “AC-2DPhC” 1001 and the planar multilayer film 1003 shown in FIG. Since “AC-2DPhC” 1001 has a substantial period in two directions and the planar multilayer film 1003 has a substantial period only in one direction in the Z direction, the sum of its PTVs, the so-called synthesis vector, is naturally different. The “AC-2DPhC” 1001 and the planar multilayer film 1003 are both multilayer films, and each layer is continuous with each other.

  Examples of the periodic structures having different PTV sums include periodic structures having different PrC lengths, different PrC directions, or different dimensions.

  As the effect of the twentieth invention, as described above, two periodic structures having different PTV sums so that the planar multilayer film 1003 has an action of confining light propagating in the thin film surface of the “AC-2DPhC” 1001. Light can be passed (transmitted and reflected) between the bodies at a constant rate. Further, the ratio can be controlled by the length and direction of the PTV. In addition, for example, in FIG. 10, instead of the planar multilayer film 1003, an appropriate three-dimensional self-cloning photonic crystal is juxtaposed around the “AC-2DPhC” 1001, thereby suppressing the output beams 1011 to 1012 in FIG. it can.

  The twenty-first invention can be explained by a combination of “AC-2DPhC” 1401 shown in FIG. 15 and the surrounding air or quartz substrate 1402. The atmosphere is a uniform medium with n≈1.0. H-type propagation (C) and (E) are manifested in combination with the surrounding atmosphere and the quartz substrate 1402. Also, the output beam 1211 can be suppressed by coating the cleaved end in FIG. 12 with metal.

  Regarding the structure of (c), for example, on the region 123 in FIG. 1, a thin film having a thickness of 120 nm by a medium having a refractive index n≈1.5 and a thin film having a thickness of 90 nm by a medium having a refractive index n≈2.1 are alternately arranged. In addition, the layer 123 may be stacked while the uneven shape of the region 123 is maintained.

  The following effects can be obtained by joining periodic structures having different sums of PTVs in the Z direction. First, by connecting a plurality of PhCs having different PTV directions in series, for example, by H-type propagation (E), a plurality of beam branching directions traveling in the same direction as the transmitted light according to Snell's law can be obtained. Next, by connecting a plurality of constituent substances or a plurality of PhCs having different periods on the XY plane in series, the above-described H-type propagation (E) can be obtained in a wide wavelength range, for example. In the case of AC-PhC, the heterostructure PhC has already been realized by changing the period of unevenness for each region in the substrate and changing the thickness of the multilayer film (see Patent Document 1).

6). Description of the 22nd Invention Hereinafter, the 22nd invention will be described in detail with reference to the drawings.

  In order to develop the H-type propagation, it is preferable to prepare the periodic structure according to any one of the first to fifteenth inventions in a large area, so that thin-film PhC, particularly AC-PhC, is currently used. desirable. Actually, in the AC-PhC having the structure shown in FIG. 1, in general, the average incident direction of the deposition or etching particles is inclined with respect to the substrate. Preparing the periodic structure of the invention in a large area can be realized. A specific manufacturing method will be described below with reference to the drawings.

  FIG. 17 is a front view showing the direction of the deposited particles or etching particles incident on the substrate and the substrate. Reference numeral 1701 denotes a convex portion formed on the substrate, reference numeral 1702 denotes a concave portion formed on the substrate, and reference numeral 1703 denotes an average incident direction of deposited particles or etching particles. Reference numerals 1704 and 1705 denote vertices of the convex portions.

  FIG. 18 is a top view showing the direction of the deposited particles or etching particles incident on the substrate and the substrate. Reference numeral 1801 denotes the upper surface of the substrate, reference numeral 1802 denotes the average incident direction of the deposited particles or etching particles, and reference numeral 1803 denotes the direction of the period of the irregularities formed on the substrate.

  FIG. 19 is a top view showing the positional relationship between the target and the substrate. Reference numeral 1901 denotes a target, reference numeral 1902 denotes a substrate, reference numeral 1903 denotes the direction of the period of unevenness formed on the substrate, and reference numeral 1904 denotes the average incident direction of the deposited particles, etching particles, or etching particles.

  FIG. 20 is a front view and a side view showing the positional relationship between the target and the substrate and the incident direction of the deposited particles, etching particles, or etching particles. 20A is a front view, and FIG. 20B is a side view.

  The twenty-second aspect of the invention can be explained by the incident direction of the substrate and the deposited particles or etching particles shown in FIGS. 17 to 20 with respect to the substrate. In producing the AC-PhC shown in FIG. 1, the average value in the incident direction of the deposited particles or the etching particles on the substrate having the two-dimensional or one-dimensional period of unevenness or sawtooth as shown in FIG. Manufactured with a film formation process concentrated in a specific direction (anisotropic deposition or anisotropic etching), and the average incident direction 1703 of the incident angle of deposited particles or etched particles with respect to the substrate is oblique to the substrate Is desirable. Further, as shown in FIG. 18, the angle formed by the period 1803 of the unevenness formed on the substrate 1801 and the average incident direction 1802 of the deposited particles or etching particles is between 0 ° and 45 °, preferably 0 ° to 10 °, most Preferably it is 0 degree. When the angle is 0 degree, the angle between the second PTV 202 in FIG. 2 and the XY plane (the plane including the first and third PTVs) is minimized, and the degree of symmetry breaking is maximized.

  The simplest method for the two-dimensional periodic structure is that the substrate is arranged off the axis of the target (displaced from just above) as shown in FIGS. 19 and 20, and the direction 1903 of the period formed on the substrate and the cylindrical shape In other words, the sputtering method is used in such a manner that the direction connecting the center of the target 1901 and the center of gravity of the substrate are parallel to each other. In the sputtering method, the deposition particles jumping out of the target have directionality (the particle flying direction is not random), and the deposition particles scattered off the axis of the target have directivity in the average incident direction 1904. Therefore, more particles are accumulated on the vertex 1705 of the convex portion than the vertex 1704 of the convex portion, and as a result, AC-2DPhC shown in FIG. 1 is obtained.

  As for the three-dimensional periodic structure, an in-plane pattern having a two-dimensional period of a square lattice as described in FIG. 3B in page 231 of Non-Patent Document 2 is provided directly above (off-axis) the target. It is convenient to arrange the substrate so that the direction of the period formed on the substrate and the average incident direction of the deposited particles or etching particles are about 45 degrees from each other. On the other hand, in order to obtain a desired propagation direction, it is possible to use the angle formed by the direction of the period formed on the substrate and the average incident direction of the deposited particles or etching particles.

  For example, the angle formed by the average incident direction of the deposited particles or etching particles and one of the period of irregularities (referred to as period 1) is 0 degree, and the other is the other of the average incident direction of the deposited particles or etching particles and the period of irregularities ( If the angle formed by (cycle 2) is 90 degrees, the propagation of H-type propagation (A) and (E) occurs only in the direction of cycle 1. If the angle formed by the average incident direction of the deposited particles or etching particles and the period 1 is 45 degrees, the propagation of the H-type propagations (A) and (E) occurs in the directions of the period 1 and the period 2. The ratio of the intensity of the H-type propagation (E) light generated in the direction of the period 1 and the intensity of the H-type propagation (E) light generated in the direction of the period 2 can be adjusted by the value of the angle.

  On the other hand, in the construction method in which the deposited particles have directivity in a direction perpendicular to the substrate and the etching particles enter the substrate obliquely (has directivity in a direction not perpendicular to the substrate), the period shown in FIG. A structure can be manufactured.

  Further, the two-dimensional PhC manufacturing method using PrC shown in FIG. 16 can be realized by forming a film by self-cloning on a substrate having irregularities such as a blazed diffraction grating. As a method of manufacturing a substrate having irregularities such as a blazed diffraction grating, it is effective to perform sputter deposition under conditions suitable for a step-type blazed diffraction grating. The positional relationship between the target and the substrate may be directly above. Note that a substrate having a cross-sectional shape such as a blazed diffraction grating can be manufactured by nanoimprinting.

7). Description of the 23rd to 25th Inventions Hereinafter, the 23rd to 25th inventions will be described in detail with reference to the drawings. The above first to twenty-first inventions can be further expanded in application range by combining with other related technologies and other devices.

  The first to fifteenth inventions do not exhibit their functions unless there is a separate electromagnetic wave source (light source). In addition, since the eleventh to fourteenth inventions have polarization dependency due to the breaking of symmetry, it is effective to separately use them in combination with a polarization separation element, a polarizer, a phase plate, or the like. It is also effective to combine with a reflection means such as a lens or a metal mirror, which is a conventional device for controlling the propagation of light.

  On the other hand, if the beam is reciprocated between the combination of the periodic structure showing the H-type propagation and the mirror, the number of beams can be increased to the calculation formula. In addition, if a plurality of parallel beams and lenses generated as a result of H-type propagation are combined, a plurality of beams generated from the same light source can be condensed at one point. An optical recording device can be obtained by arranging a photoconductor at this condensed point.

  Further, the beams traveling parallel to each other generated by the H-type propagation (E) have substantially the same polarization state, but the polarization extinction ratio is deteriorated, so that the polarizer, the reflection type polarization separation element, and the walk-off type polarization separation are obtained. It is desirable to recover the polarization extinction ratio in combination with an element.

  In addition, when light is used for signal transmission, a modulator and a light receiver are necessary, and it is also effective to combine a reflecting means and a diffraction grating as appropriate. Further, in the case where beams parallel to each other generated by the H-type propagation (E) are used individually, it is desirable to combine them with an optical waveguide.

  Next, the twenty-fourth invention will be explained. By using the device according to the twenty-fourth invention, it is possible to make a beam emitted from one light source incident on an optical element having a function of branching one beam into a plurality of beams propagating in the same direction. Furthermore, if a plurality of the optical elements having different beam branching directions are used, the intensity of the beam can be dispersed and made substantially uniform within the effective range of the optical elements. A similar effect can also be obtained by combining a periodic structure that generates the H-type propagation, in which one parallel beam branches into a plurality of beams propagating in the same direction, a reflective polarizer, a mirror, a wave plate, and the like. . There may be a plurality of beams incident from the outside first.

  Next, a twenty-fifth aspect of the invention is described. The twenty-fifth invention is effective, for example, as an optical recording apparatus. In some cases, the device may include a charge coupled device array light receiver, a CMOS sensor array, or reflection means having the same reflection direction as that of the periodic structure. In particular, the periodic structure splits incident light into two or more beams propagating in the same direction, and at least one of the two or more beams transmits or reflects the spatial light modulator, and the 2 A device that condenses at least two beams including a beam transmitted or reflected from the spatial light modulator among two or more beams at the same position in the photosensitive member through the lens is effective as an optical recording apparatus. . In particular, if one beam is used to branch a beam into a plurality of beams propagating in the same direction and one lens can be used, two beams can be accurately collected at one point (however, the spread of the spot is ignored) ). Furthermore, if a two-dimensional intensity distribution change is given to one or both of the two beams, it can be used for holographic recording.

8). A method for controlling the coupling efficiency between the antisymmetric mode of the photonic crystal and the external plane wave Further, the inventor has also studied “a method for controlling the coupling efficiency between the antisymmetric mode of PhC and the external plane wave”. The following (1) and (2) are known in Non-Patent Document 4 and can be used as they are.
(1) The coupling efficiency between the antisymmetric mode of PhC and the external plane wave depends on the incident angle.
(2) The coupling efficiency between the antisymmetric mode of PhC and the external plane wave depends on the number of layers (period number).

  In addition, the matter explained so far mainly on light is applicable to electromagnetic waves in general.

  As described above, the peculiarities of the periodic structure according to the first to nineteenth inventions are clarified. Therefore, in order to distinguish from conventional periodic structures and PhC, special names are given to the periodic structures corresponding to the first to tenth inventions. That is, PrC and BAS shown in FIG. 2 and equivalent PrC and BAS are “2D-collapsed ACBC”, and the periodic structure by “2D-collapsed ACBC” is “2D-collapsed ACPC”, and PrC shown in FIG. PrC and BAS expanded to 3D and BAS are "3D-collapse ACBC", the periodic structure by "3D-collapse ACBC" is "3D-collapse ACPC", PrC and BAS shown in Fig. 16 and equivalent PrC and BAS are referred to as “2D-inside-inverted ACBC”, and the periodic structure formed by “2D-inside-inside ACBC” is referred to as “2D-inside-inverted ACPC”.

The light propagation control element according to the first embodiment of the present invention will be described in detail with reference to the drawings.
The periodic structure formed on the substrate shown in FIG. 1 is used, and SiO ₂ is used as a medium with n≈1.5, and niobium pentoxide (hereinafter, Nb ₂ O ₅ ) is used as a medium with n≈2.4.

  A method of manufacturing “2D-collapse ACPC” shown in FIG. 1 will be described. The structure of FIG. 1 can be manufactured according to the self-cloning method and the twenty-second invention by first forming irregularities on a substrate base material, then forming a shaping layer on the substrate, and then laminating a multilayer film.

  First, the substrate 124 will be described. FIG. 21 is a schematic perspective view showing the substrate 124 shown in FIG. Reference numeral 2101 denotes a substrate base material, and reference numeral 2102 denotes an uneven protrusion formed on the substrate base material. The periodicity of the irregularities formed on the substrate base material has only in the X direction and is uniform in the Y direction.

  A fused silica is used as the material of the substrate 124, and a rectangular fused with a period of 410 nm (the height and width of the protrusions (projections) is 205 nm) by a lithography process using electron beam (EB) exposure and dry etching on a flat fused quartz substrate. Are formed (hereinafter referred to as a substrate pattern). Supplementing the method of forming a substrate pattern on the substrate, a process combining EB lithography and etching, a process combining lithography and etching by light or X-ray exposure, or nanoimprinting can be used. In addition, if an opaque material film is used in an ultraviolet region of sufficient thickness laminated on a transparent substrate or an opaque material substrate in the ultraviolet region, irregularities on the substrate can be formed even in a process combining interference exposure and etching. . In this embodiment, since the shape accuracy of the unevenness is excellent and etching is easy, it is preferable to employ a process in which lithography and etching by EB are combined with a fused quartz substrate.

Next, the intermediate layer (shaping layer) 112 will be described. FIG. 22 shows the substrate 124 and the shaping layer 112 shown in FIG. Reference numeral 2201 represents the substrate shown in FIG. 21, and reference numeral 2202 represents the shaping layer (same as the intermediate layer 112). The periodicity is only in the X direction.
After forming irregularities on the substrate shown in FIG. 21, a SiO ₂ film is deposited on the substrate by an rf bias sputtering method (rf sputtering with an effect of sputter etching) under appropriate conditions, thereby forming a triangular shaped shaping layer. Form. At this time, as shown in FIGS. 19 and 20, by removing the substrate from directly above the target and making the radial direction of the target and the periodic direction of the substrate substantially the same direction, the cross section in the ZX plane is a non-isosceles triangle (three Triangular shaped layers with different side lengths can be realized.

Next, a multilayer film composed of the SiO ₂ layers 101 to 111 and the Nb ₂ O ₅ layers 113 to 123 shown in FIG. 1 will be described. If the Nb ₂ O ₅ and SiO ₂ layers are alternately laminated on the substrate on which the shaping layer 2202 shown in FIG. 22 is laminated, the sectional shape shown in FIG. 1 is obtained. The lamination of the SiO ₂ layer and the Nb ₂ O ₅ layer is performed by rf bias sputtering.

FIG. 23 is an electron micrograph of a cross section in the ZX plane of a two-dimensional self-cloning PhC (2D-collapsed ACPC) actually produced. The stacking cycle is 11 cycles. In FIG. 23, the layer with the appearance close to white is the Nb ₂ O ₅ layer, the layer with the appearance close to black is the SiO ₂ layer, and the substrate and the shaping layer are made of materials of the same composition, so they cannot be distinguished.

  FIG. 23 shows that the growth direction of the film is inclined by about 4 degrees. In FIG. 23, the shape is not stable up to the initial third layer of the multilayer film, and the shape is stabilized from the fourth layer, but there is no particular problem. Note that the film growth direction is the direction of the third PTV, and the direction in which the third PTV is projected onto the XY plane in FIG. 1 is the direction in which the propagation or branching of light from H-type propagation (A) to (E) occurs. Become.

Next, it supplements about the preparation methods of a periodic structure. When stacking Nb ₂ O ₅ films, the target is, for example, an Nb ₂ O ₅ sintered body, the deposition gas is, for example, a mixed gas of argon and oxygen, and the gas pressure is, for example, 0.3 Pa to 1.0 Pa (preferably from 0.4 Pa). 0.8 Pa, more preferably 0.5 Pa to 0.7 Pa, which is a condition that balances the residence stress and density of the film, and the oxygen gas flow rate ratio is, for example, about 10% (preferably 5% or more and 20% or less, more preferably It is preferable that the film forming speed (the amount of increase in film thickness per hour) is 7% or more and 15% or less of a condition that balances the stability of the composition. When laminating the SiO ₂ film, the target is, for example, quartz, the deposition gas is, for example, a mixed gas of argon and oxygen, and the gas pressure is, for example, 0.3 Pa to 2.0 Pa (preferably 0.6 Pa to 1.8 Pa, more preferably It is preferably 0.8 Pa to 1.5 Pa, which is a condition that balances the residence stress and density of the film. The bias to be applied is preferably about several tens of volts, although the optimum value has dependency on other film forming conditions and device dependency. The substrate heating temperature in the thin film process is usually preferably 0.3 times or more the melting point of the medium, but preferably 0.3 to 0.5 times, more preferably a balance between the film density and the time required for heating and cooling. It is 0.31 times or more and 0.4 times or less. In this embodiment, the substrate heating temperature is preferably about 600K.

  Also, a 2D-collapsed ACPC is produced by a combination of the rf bias sputtering method, the ECR sputtering method, rf magnetron sputtering without applying a bias on a substrate shaped into a pyramid type, and etching such as sputtering, ion gun, and RIE. Is possible.

  The film growth direction (equal to the PTV direction) can be controlled by changing the angle between the radial direction of the target and the periodic direction of the substrate, and can also be controlled by the distance between the target and the substrate. is there. In addition, “3D-collapse ACPC” can control the direction of PTV by adjusting the angle formed by the average incident direction 1802 of the etching particles in FIG. 18 and the unevenness period 1803 between 0 degrees and 90 degrees, for example. .

In this example, Nb ₂ O ₅ was used as a high refractive index medium in PhC, but SiC, SiOx (where 0 <x <2), tantalum pentoxide (Ta ₂ O ₅ ), titanium dioxide (TiO ₂ ), gallium. Any of n ≧ 2 media such as nitride (GaN), aluminum nitride (AlN), zinc oxide (ZnO), ZnSe, ITO (Indium Thin Oxide), hafnium oxide (HfO ₂ ), a-SiO, SiN, etc. It is also effective to use in combination. It is also effective to use a combination of any of n ≦ 1.6 media such as magnesium fluoride (MgF) and calcium fluoride (CaF) as the low refractive index medium.

  The periodic structure shown in FIG. 1 (and FIG. 23) exhibits the H-type propagation. FIG. 24 is a graph showing the transmittance wavelength dependency of the periodic structure formed on the substrate shown in FIG. 1 at the time of vertical incidence of the beam transmitted according to Snell's law. FIG. 24A shows characteristics corresponding to the case where the incident beam is a TE polarized wave, and FIG. 24B shows characteristics corresponding to the case where the incident beam is a TM polarized wave. As shown in FIGS. 24 (a) and 24 (b), the periodic structure shown in FIG. 1 (and FIG. 23) has transmittance wavelength dependency different from that of conventional optical elements such as diffraction gratings and wavelength selective filters. I understand.

  In the present embodiment, an optical branching device (star coupler) used for optical communication by using an H-type propagation (E), for example, by installing an optical fiber with a lens at an incident position of light and an outgoing position of branched light. Available as Further, by splitting the parallel beam from one laser light source into three, a three-beam pickup for tracking and reading / writing can be easily realized and can be used for an optical recording apparatus.

In addition, using H-type propagation (I), if beams of different wavelengths are incident in the same direction and in the same direction as the separation distance of each wavelength from the Z direction with respect to the present embodiment, it is used as a wavelength synthesizing mechanism. For example, the structure of a pickup that reads signals from DVDs and CDs can be simplified.
Further, if a beam having a wide spectrum is incident on the present embodiment from the Z direction, it can be used as a wavelength branching mechanism, for example, as a spectroscope.

  As another invention, if a periodic structure that generates the H-type propagation (E) is used and the same number of lenses as the beam are used, one pickup corresponding to a plurality of types of optical recording disks using the same wavelength is used. Can be realized with a stand.

  A holographic optical recording apparatus according to Embodiment 2 of the present invention will be described in detail with reference to the drawings. This embodiment is a holographic optical recording apparatus using H-type propagation.

  FIG. 25 is a side view showing the basic configuration of the holographic recording apparatus. The holographic recording apparatus includes a laser light source 2501, a lens 2502, a periodic structure 2503 having an optical branching function by H-type propagation (E), a DMD 2504 (digital micromirror device) that is a spatial light modulator integrated adjacently, and a mirror. 2505, a reflective polarization separation element 2506, a quarter-wave plate 2507, a lens 2508, a recording medium 2509, and a two-dimensional image sensor (CMOS sensor). Hereinafter, a device having an optical branching function based on H-type propagation (E) to H-type propagation (K) is abbreviated as “HBS”.

  FIG. 26 is a side view showing the operation during recording. Reference numeral 2601 is an incident parallel beam to the HBS 2503, reference numerals 2602 and 2603 are output beams output from the HBS 2503 to the transmission side, reference numeral 2604 is a beam reflected by the mirror, reference numeral 2605 is a beam reflected by the DMD 2504, reference numeral 2606 and reference code Reference numeral 2607 denotes an output beam output from the HBS 2503 to the reflection side.

  The operation during recording will be described with reference to FIG. After the parallel beam output from the laser light source enters the HBS, it is output as two beams propagating in parallel from the transmission side. Thereafter, one of the two beams is given two-dimensional page data by the DMD, and the other beam is reflected by a mirror made of a dielectric multilayer film formed on the same substrate as the DMD. Then, each beam is condensed at the focal position of a common lens, and data is recorded in the form of interference fringes on a recording medium made of a photosensitive material.

  FIG. 27 is a side view showing the operation during reproduction. Reference numeral 2701 denotes an incident parallel beam to the HBS 2503, reference numerals 2702 and 2703 are output beams output from the HBS 2503 to the transmission side, reference numeral 2704 is a beam reflected by the mirror, reference numeral 2705 is a beam reflected by the recording medium 2509, reference numeral 2706 Represents the beams reflected by the reflective polarization separation element 2506, respectively.

  The operation during playback will be described with reference to FIG. A parallel beam output from a laser light source with a lens enters the HBS, and then is output as two parallel propagating beams from the transmission side. After that, one of the two beams is blocked by DMD in which all the pixels are in the off state, and the other beam is reflected by a mirror made of a dielectric multilayer film formed on the same substrate as the DMD. The reflected beam passes through the reflective polarization separation element and the quarter-wave plate, and is then focused on the focal position by the lens, and is given intensity distribution information in the form of interference fringes on the recording medium. The beam to which the information is applied and reflected from the recording medium is reflected by the reflective polarization separation element and enters the two-dimensional image sensor.

  Signal processing and the like may be the same as those of conventional holographic recording. In principle, the DMD is turned off at the time of reproduction. However, even if the DMD is on, the DMD reflected light and the mirror reflected light are incident at sufficiently separated positions of the two-dimensional image sensor, but the reproduction is not adversely affected. Since the photosensitive material of the recording medium may be deteriorated, it is desirable to turn it off.

  FIG. 28 is a diagram showing an HBS used in this embodiment. The first region 2801 and the third region 2803 in the HBS are self-cloning type three-dimensional PhC “3D-collapsed ACPC”, and have a square lattice-like periodic structure with a period of unevenness of 180 nm on the XY plane. The second region 2802 is “2D-collapsed ACPC” in which the period of unevenness of the substrate manufactured in the same manner as in FIG. 1 is 205 nm. The fourth region 2804 is a one-dimensional periodic structure. Reference numeral 2805 denotes a beam entrance and exit position, and reference numeral 2806 denotes a beam exit position.

  The HBS 2503 will be described with reference to FIG. The first region 2801 in the HBS 2503 is a self-cloning type three-dimensional PhC, and has a square lattice-like periodic structure with a period of unevenness of 180 nm on the XY plane. The second region 2802 is “2D-collapsed ACPC” in which the unevenness period of the substrate manufactured in the same manner as in Example 1 is 205 nm. The third area 2803 is the same as the first area 2801. The fourth region 2804 is a one-dimensional multilayer film having no period in the XY direction. The first region 2801 has a band gap at a wavelength of 405 nm, and suppresses leakage light from the second region 2802 in the Y direction. The size of the second region 2802 is 4 mm so that two beams are emitted. The beam emitted to the reflection side can be used for monitoring a laser light source. The second area 2802 may be “2D-inverted ACPC”.

  In general, in holographic recording, as described in Patent Document 2, an optical system with multiple reflections from the same laser light source is used, and information light and reference light are processed by different parts, so that they are vulnerable to vibration. It is said that the stability against the environmental change is poor (for example, the surface shake generated when the disk is rotated). However, if the HBS shown in FIG. 28 is used and the optical system in FIG. 25 is used, the information light and the reference light are always focused on the same point even if each component is misaligned or angularly displaced, enabling stable recording. It is.

  An apparatus according to Embodiment 3 of the present invention will be described in detail with reference to the drawings. The present embodiment is an apparatus that performs uniform light intensity distribution and polarization conversion using H-type propagation. The apparatus according to the present embodiment is particularly suitable for use in uniform light intensity in a projection display (projector) and polarization conversion from a non-polarized light source.

  Conventionally, in a liquid crystal projector, linearly polarized light has been obtained from a lamp which is a non-polarized light source by using a ps polarization conversion element described in Patent Documents 3 and 5.

  An optical integrator (hereinafter abbreviated as OpI) is used to effectively apply a light beam having a circular cross section from a lamp or a reflecting mirror attached to the lamp to a rectangular liquid crystal panel. Examples of OpI include those described in Patent Document 4 and Patent Document 5.

  In this embodiment, a periodic structure showing H-type propagation is used, the light intensity is made uniform and polarization-converted with a simple and small configuration, and the polarization-compensated OpI (hereinafter referred to as the output light is concentrated in one direction). Abbreviated as “PC-OpI”).

  FIG. 29 is a side view of PC-OpI and a diagram showing light propagation inside PC-OpI. The PC-OpI shown in FIG. 29 includes an optical fiber 2901 with a lens, a mirror 2902, a quarter wavelength plate 2903, HBS groups 2904 to 2907, a PhC reflection type polarization separation element 2908, and a light shielding plate 2909. Reference numeral 2910 represents a parallel beam output from the optical fiber 2901 with a lens. The HBS groups 2904 to 2907 arranged in series with respect to the traveling direction of the beam from the optical fiber 2901 with a lens, the reflection type polarization separation element 2908 by the two-dimensional PhC, and the mirror 2902 are inclined with respect to the parallel beam 2910 by 3 degrees. The distance between the HBS 2904 and the mirror 2902 is 20 mm.

  The operation will be described with reference to FIG. First, the output light 2910 from the optical fiber 2901 with a lens is incident on the HBS 2904 via the quarter-wave plate 2903, branched into three beams on the transmission side, and output. The three beams output to the transmission side of the HBS 2904 are incident on the next HBS 2905, and the beams are branched into nine on the transmission side and output. As described above, the number of beams output to the transmission side increases as the HBS at the subsequent stage increases.

  Further, the output light 2910 from the optical fiber 2901 with a lens enters the HBS 2904 via the quarter-wave plate 2903, and is branched into three beams on the reflection side and output. The three beams output to the reflection side of the HBS 2904 are transmitted through the quarter-wave plate 2903, reflected by the mirror, transmitted through the quarter-wave plate again, and incident on the HBS 2904 again. The light is incident on the HBS 2904 again, and the beam is split into nine beams on the transmission side and output. However, since there are some overlapping beam positions, the actual number of beams is five. Further, the position where the light is incident again on the HBS 2904 and the beam is branched into nine on the transmission side and outputted is output light 2910 from the optical fiber 2901 with a lens incident on the HBS 2904 via the quarter-wave plate 2903, The position is different from the position where the light is branched into three beams on the transmission side. Although not described, the beam incident on the HBS 2904 again is divided into nine beams on the reflection side (actually, five beams are overlapped) and output.

  As described above, the number of beams increases each time transmission and multiple reflection are repeated between HBSs, the reflection type polarization separation element 2908, and the mirror 2902 (such as, for example, a chain reaction in fission).

  Since there are many beams that are repeatedly reflected and branched between the HBS, between the reflective polarization separation element 2908 and the HBS, between the HBS and the mirror, etc., the intensity at which the light transmitted through the reflective polarization separation element 2908 is overlapped by many beams It becomes linearly polarized light with a uniform distribution.

  Further, since the mirror 2902, the HBSs 2904 to 2907, and the reflective polarization separation element 2908 are arranged in parallel and the incident light is a parallel beam, the light transmitted through the reflective polarization separation element 2908 is so-called telecentric light. Furthermore, if a large number of optical fibers with lenses are installed, a substantially uniform light can be obtained with a larger area. Further, light with low uniformity at the outer peripheral portion of the light transmitted through the reflective polarization separation element 2908 can be blocked by the light shielding plate 2909.

  The HBS group will be described. “2D-collapsing ACPC” in the HBS group has light branching directions that differ by 45 degrees around the Z axis, and each has a beam separation function of 2 mm. In addition, a one-dimensional planar multilayer film that blocks in-plane propagation is arranged around “2D-collapse ACPC”. However, in order to cut off the in-plane propagation more efficiently, it is effective to use a three-dimensional periodic structure or a metal film in place of the one-dimensional planar multilayer film with an increase in manufacturing cost. Although the manufacturing cost also increases, the uniformity of the output light in FIG. 29 improves as the number of HBS increases.

  Other parts will be described. The optical fiber 2901 with a lens is connected to a green laser light source, and the beam diameter of the output beam is 1 mm. The reflective polarization separation element 2908 has an action of selecting the final output light as linearly polarized light having a predetermined direction, and the polarization component orthogonal to the polarization direction of the output light included in the incident light with respect to the polarization separation element is reflected, Re-enter the HBS. The reason why the two-dimensional PhC is used as the reflective polarization separation element is that the transmittance and the reflectance can be arbitrarily set, and the transmittance in the transmitted polarization direction is about 40% (preferably 20% or more and 60% or less, more Preferably, the light intensity distribution can be made more uniform.

  The mirror 2902 is made of a dielectric multilayer film, and the multilayer film is removed only at the light incident position from the optical fiber 2901 with a lens, and has an effect of reflecting the return light of the periodic structure having an optical branching function. A mirror having an aluminum film adhered on a transparent glass plate can be used. However, since the mirror is a flat plate mirror and does not absorb light, a dielectric multilayer film is more suitable. The quarter-wave plate 2903 has a function of changing the polarization state. The light reflected by the reflective polarization separation element 2908 is transmitted through the quarter-wave plate 2903, reflected by the mirror 2902, and again the quarter wavelength. Light that has passed through the plate 2903 passes through the reflective polarization separation element 2908 at a high rate.

  The effect of the present embodiment will be described. If the configuration shown in FIG. 29 is used, the intensity distribution is made uniform by repeating the branching and reflection of the beam, and the output light is linearly polarized. Further, since the reflecting element arranged in parallel with the parallel beam and the periodic structure having a light branching function for branching the incident light into a plurality of beams propagating in parallel, the output light has many parallel beams that propagate in the same direction The intensity distribution is maintained even in the distance after the light propagates. In general, LD light sources have high coherence and speckles occur when used as illumination. However, the light output from PC-OpI shown in Fig. 29 is a set of many beams with different optical paths, and the coherence is reduced. Has been.

  Note that a polarizing element such as a half-wave plate, a birefringent crystal walk-off polarization separating element, or a depolarizer may be inserted between the mirror 2902 and the reflective polarization separating element 2908. It is also effective to use a laser diode (LD) or LED as the light source.

  A light absorber and a photoelectric conversion device according to Example 4 of the present invention will be described in detail with reference to the drawings. The present embodiment is a light absorber and photoelectric conversion device using H-type propagation.

  A general photoelectric conversion device has a basic operation principle of utilizing a photovoltaic effect of a semiconductor (separated into electrons and holes when the semiconductor absorbs light) (see Non-Patent Document 7).

  A photoelectric conversion device using a semiconductor generally takes out carriers using a semiconductor junction. The light absorption process of semiconductors is broadly divided into interband absorption, band-localized level absorption, localized level-level absorption, and intraband absorption. In interband absorption and band-localized level absorption, free carriers Will occur. Localized interlevel absorption and in-band absorption are not involved in free carrier generation, and absorbed photon energy is converted to thermal energy.

  There is a loss in the energy conversion of the photoelectric conversion device. This loss is absorbed by the free carrier generator, the first loss due to the fact that 100% of the photons do not reach the free carrier generator, and the second loss due to the fact that the free carrier generator cannot absorb 100% of the photons. It is divided into a third loss due to the fact that photons are not converted to 100% electric energy, and an electric fourth loss.

  In light absorbers (layers) used in photoelectric conversion devices, particularly solar cells, a thick light absorption layer is necessary to improve the light absorption efficiency. Conversely, when a thick light absorption layer is used, There was a dilemma in which the recombination of holes and holes resulted in low conversion efficiency to electrical energy.

  On the other hand, when a plane wave is incident on an arbitrary position in the thin film optical element as in the H-type propagation (A) and (B), the plane wave is incident on the surface or in an arbitrary angle range, light is incident on the surface of the optical element. Can propagate a large amount of light with a light absorber (film) having a small light absorption rate, and the dilemma can be eliminated. The constituent medium of the periodic structure used in that case needs to contain fluids, such as a semiconductor, a transparent conductor, or electrolyte solution.

Based on the above, the photoelectric conversion device according to Example 4 will be described in detail with reference to the drawings. FIG. 30 is a schematic side view of a photoelectric conversion device based on “2D-collapsed ACPC” made of amorphous SiC (hereinafter “a-SiC”) and thin film polycrystalline silicon (hereinafter “μc-Si”). As shown in FIG. 30, the photoelectric conversion device includes a glass substrate and a SiO ₂ barrier layer (not shown) on the glass substrate, a back electrode 3001 that also serves as a mirror, a transparent conductive film (TCO) 3002 made of ITO, 2D-collapsed ACPC "3003, transparent conductive film 3004, electrodes 3005 and 3006, and SiO ₂ layer 3007. The basic structure is a pin / pin /... / Pin two-terminal connection stack type.

The features of this embodiment are mainly the following three points.
(1) Use PhC “2D-collapse ACPC” which has conductivity in the Z direction and shows H-type propagation (A), (B) and (C).
(2) Light incident from outside propagates while being confined inside PhC by H-type propagation (A), (B) and (C), and is absorbed, thereby increasing light absorption efficiency compared to bulk materials. Let
(3) By the above, the light absorptance derived from the electron band structure is compensated by controlling the photon band structure and the light propagation direction.

  Specifically, the light incident perpendicularly to the surface (incident in the −Z direction) is propagated in the in-plane X direction to efficiently absorb photons and take out carriers in the ± Z directions. Thereby, a thinner light absorption layer enables sufficient light absorption and suppresses recombination loss of electrons and holes. In addition, the energy of photons having a wavelength longer than the absorption edge can be used (free carriers generated by band-localization absorption can be extracted).

  FIG. 31 shows PrC and BAS of “2D-collapse ACPC” 3003 shown in FIG. FIG. 31 (a) shows PrC, the length of the first PTV 3101 parallel to the X direction is 350 nm, the length of the second PTV 3102 is 161 nm, has an angle of 86 degrees with respect to the XY plane, and the ZX plane. The third PTV is uniform in the Y direction, and the length cannot be uniquely defined (arbitrary). Reference numerals 3103 to 3106 denote lattice points. FIG. 31 (b) is a BAS, and is a cross-sectional view of a plane parallel to the plane including the first PTV 3101 and the second PTV 3102 (here, parallel to the ZX plane) and including the midpoint of the third PTV. It is.

  The BAS in FIG. 31 (b) includes regions 3107 and 3108 occupied by i-type μc-Si, a region 3109 occupied by n-type μc-Si, and regions 3110, 3111 and 3112 occupied by p-type a-SiC. The region 3107 and the region 3108 are continuous as a periodic structure. The same applies to the regions 3110, 3111 and 3112. In terms of the refractive index distribution, the regions 3107 and 3108 and the region 3109 can be regarded as one body. The i-type μc-Si layer has a thickness of about 100 nm, the n-type μc-Si layer has a thickness of about 10 nm, and the p-type a-SiC layer has a thickness of about 50 nm.

  Next, the medium used will be described. “A-SiC” is a p-type semiconductor with Eg≈2.0 to 2.1 eV and n≈2.1 (at a wavelength longer than the absorption edge). On the other hand, μc-Si is Eg≈1.1 eV and n≈3.4 (at a wavelength longer than the absorption edge). Although the “μc-Si” layer is divided into a non-doped layer and an n-type semiconductor layer, the refractive index is the same, and it can be regarded as one when considering the behavior with respect to photons as PhC.

  In this embodiment, μc-Si is used as the high refractive index medium in PhC. However, any medium having n≈3 can be substituted. For example, it is also effective to use a-Si: H instead of μc-Si. “A-Si: H” has higher light absorption in the visible region than μc-Si, but is inferior in electrical characteristics (carrier transport characteristics), and the minority carrier diffusion length is 100 nm or less (non- (See Patent Document 7). However, the thickness of the a-Si: H layer may be 100 nm or less in PrC and BAS of light absorbers of about 2000 nm from visible light using a-Si: H by PhC. While suppressing the problems of a-Si: H, it is possible to use the advantages (large bottom absorption on the longer wavelength side than the absorption edge, large band gap energy, etc.). Examples of the material satisfying n ≧ 3 in the transparent wavelength band include semiconductors such as Si, Ge, SiGe, gallium arsenide, and aluminum gallium arsenide compounds.

The material of the ideal light absorption layer (i layer) in this embodiment is described as follows. (1) The band gap energy of electrons is large.
(2) As the absorption coefficient becomes longer than the absorption edge, the absorption coefficient does not decrease suddenly but decreases gently (the bottom absorption is large. There is absorption between bands and localized levels).
(3) The refractive index is large (n ≧ 3).
(4) The resistivity is small.
(5) Electrical junction is possible with the p-type transparent conductive film.

  Next, a window layer (a layer that does not absorb photons and has electrical conductivity) will be described. “A-SiC” is a wide-bandgap semiconductor that has low light absorption in the solar spectrum region and is suitable for use as a window layer in photoelectric conversion devices for sunlight. Can also be used (see Non-Patent Document 7).

Next, the overall configuration of the present embodiment will be described. First, a SiO ₂ barrier layer is formed on a white plate glass having a thickness of 5 mm, and a metal electrode is formed thereon. Further, ITO is laminated thereon by sputtering to about 500 nm. Next, the ITO layer is patterned using a photosensitive resist and mask exposure, and pyramidal irregularities are formed by etching. Thereafter, a triangular shaped layer made of ITO is laminated by bias sputtering. Next, the following steps (1) to (3) are repeated for 11 cycles or more.

(1) A-Si is deposited to a thickness of 10 nm by sputtering deposition, annealed with an excimer laser to be polycrystallized, and then impurity doping by ion implantation and lamp annealing is performed to form n-type μc-Si. The impurity doping to the n layer can be performed by using an argon, hydrogen, or PH ₃ mixed gas at the time of film formation by rf sputtering, or a target to which the impurity is added can be used.

(2) A-Si is deposited to a thickness of 100 nm by sputtering deposition and annealed with an excimer laser to be polycrystallized.

(3) a-SiC is formed in accordance with the self-cloning method described above. “A-SiC” is formed by rf bias sputtering of a SiC sintered compact target with argon and C ₂ H ₂ . As another method, the Si target can also be obtained by rf sputtering with argon and C ₂ H ₂ (reactive sputtering). SiC is doped with aluminum as an impurity to form a p-type semiconductor.

Finally, an ITO layer is formed by bias sputtering under conditions for filling the unevenness (increasing the bias amount). The structure shown in FIG. 30 is completed by forming a comb-shaped metal electrode on the ITO layer. Furthermore, it is also effective to form an SiO ₂ film as an antireflection layer by an arbitrary film forming method. In this embodiment, a “2D-collapsed ACPC” layer is formed by rf sputtering, but can also be realized by a combination of ECR sputtering, CVD method and etching.

  In this embodiment, light is incident from the p layer side because the hole transport property is inferior to the electron transport property, and it is more advantageous to enter light from the p layer side (non-patent document). Reference 7). In addition, one μc-Si layer in this example is 100 nm, which is thinner than the thickness (100 μm or more) of a thin-film multilayer solar cell using ordinary μc-Si, but the light is near the surface of the μc-Si. It is particularly strongly absorbed to generate electron-hole pairs, and the electron-hole pairs are separated and moved to the junction. Therefore, it is desirable that light absorption be performed in a portion close to the junction. A thin Si layer is advantageous for high efficiency. In this embodiment, “2D-collapsed ACPC” is used, but if “3D-collapsed ACPC” is used, light can be efficiently absorbed in a wider wavelength band.

Next, it supplements about PrC and BAS of a PhC part. The PhC portion in the photoelectric conversion device of FIG. 30 can have a configuration in which the distribution of n is substantially the same and electrically different. Even if the high refractive index portion is a multilayer film of p-type a-Si: H, i-type a-Si: H, and n-type a-Si: H, and the low refractive index portion is SnO ₂ PrC and BAS, Since the nick band structures are almost the same and are electrically connected, an excellent photoelectric conversion device as in FIG. 30 can be realized.

It is also effective to use SnO ₂ or ZnO instead of ITO.

  Furthermore, in this example, one kind of periodic structure composed of PrC and BAS was used. However, as described in the means for solving, a plurality of periodic structures composed of different PrC and BAS are connected in the Z direction. It is also possible to efficiently carry out photoelectric conversion by propagating incident light in the thin film plane at a wavelength. Different PrC and BAS can be realized by changing the film thickness for those having different basic lattice vector lengths, and changing the incident direction of the deposited particles or etching particles for those having different basic lattice vector directions. Further, BAS having a different refractive index distribution can be realized by changing deposited particles and dopants. In particular, it is effective to change the deposited particles of the i layer, and an effect equivalent to the stack type in the conventional solar cell can be obtained.

  In order to minimize light shielding by the electrodes, it is effective to add a prismatic cover (see Non-Patent Document 7) outside. If the refractive index of the prismatic cover is small, light leaking from the periodic structure 3003 to the prismatic cover is sufficiently small.

  A periodic structure using a fluid in part according to Example 16 of the present invention will be described in detail with reference to the drawings. The present embodiment is a periodic structure corresponding to the first to tenth inventions other than AC-PhC.

FIG. 32 is a cross-sectional view of a three-dimensional PhC produced using TiO ₂ , SnO ₂ , and iodine solution. Reference numeral 3201 represents TiO ₂ , reference numeral 3202 represents SnO ₂ , reference numeral 3203 represents an iodine solution, and reference numeral 3204 represents a substrate. The PTV of the periodic structure is in a direction inclined by 86 degrees with respect to the X direction, the Y direction, and the XY plane.

The feature of this embodiment is that a fluid is used as one of the media, and the fluid can be exchanged with the outside. Examples of liquid optical devices include wet solar cells, etc., but using an electrolyte, especially iodine solution as the liquid, and connecting electrodes externally, the periodic structure shown in FIG. 32 is also used as a wet color solar cell. Operate. As a manufacturing method, after forming a multilayer film of SnO ₂ and TiO _2, a hole into which a fluid can be injected or a groove is formed (see Patent Document 6).

When one of the media is a fluid as in this embodiment, there are advantages that the propagation characteristics can be made variable and that a chemical reaction can be generated inside the periodic structure.
Next, light propagation will be described. Also in this embodiment, light incident from the Z direction propagates in the X direction within the periodic structure. Propagation in the X direction is equivalent to confining light within the periodic structure, resulting in a wet solar cell with high conversion efficiency.

  The present invention can be suitably used in the field of optical operations such as optical branching, spectroscopy, and optical recording.

Claims (25)

  There is a periodic structure composed of two or more kinds of media having a refractive index greater than 1.2, and there is a combination in which the ratio of the refractive index between the contained media is greater than 1: 1.2, which constitutes a basic unit cell Of the first to third basic translation vectors, a plane including any axis orthogonal to the plane containing the first and second basic translation vectors and parallel to the first basic translation vector and / or the second Refractive index or dielectric constant periodically, characterized in that the dielectric constant or refractive index distribution in the unit structure and / or the basic unit cell is non-mirror symmetric with respect to a plane parallel to the basic translation vector A changing periodic structure.   There is a combination of two or more types of medium having a refractive index greater than 1.2, wherein the ratio of the refractive index between the contained media is greater than 1: 1.2, and the dielectric constant in the unit structure Alternatively, the refractive index distribution and / or the basic unit cell is non-rotationally symmetric and non-inverted symmetric, and the first and second basic translation vectors among the first to third basic translation vectors constituting the basic unit cell are Refraction characterized by being non-mirror symmetric with respect to a plane containing any axis orthogonal to the containing plane and parallel to the first basic translation vector and / or parallel to the second basic translation vector A periodic structure with periodically changing permittivity or dielectric constant.   There is a combination of two or more types of medium having a refractive index greater than 1.2, wherein the ratio of the refractive index between the contained media is greater than 1: 1.2, and the dielectric constant in the unit structure Or a periodic structure having a periodically changing refractive index or dielectric constant, wherein the refractive index distribution and / or the basic unit cell has only translational symmetry.   4. The periodic structure according to claim 1, wherein the second basic translation vector can take any length that is not zero. 5.   The angle formed by a surface including any two basic translation vectors among the first to third basic translation vectors and the remaining one basic translation vector is greater than 60 degrees and less than 90 degrees. The periodic structure described in any one of 1 to 4.   The periodic structure is formed by laminating a plurality of thin films, the thin film layer has a periodic concavo-convex structure, and the convex portions in the concavo-convex structure are convex portions having a plurality of distances from the top to the bottom. The periodic structure according to claim 1, wherein:   The length of at least one basic translation vector is 100 nm to 1000 nm, and at least one of the media included in the unit structure has a refractive index of 2 or more. The periodic structure to be described.   Electromagnetic field relative to a plane containing any axis orthogonal to the plane containing the first and second basic translation vectors and parallel to the first basic translation vector and / or parallel to the second basic translation vector Exhibits a non-mirror-symmetric eigenmode, 8. The periodic structure according to claim 1, wherein:   For an electromagnetic field that includes any axis orthogonal to the plane containing the first and second basic translation vectors and is parallel to the first basic translation vector and / or a plane parallel to the second basic translation vector The periodic structure according to claim 1, wherein the periodic structure is non-mirror-symmetric and exhibits a natural mode that is non-rotational symmetric with respect to the axis.   A plane and / or a second basic translation vector whose electromagnetic field includes any axis perpendicular to the plane containing the first and second basic translation vectors and parallel to the first basic translation vector regardless of the direction of excitation. The present invention exhibits an eigenmode that is non-mirror-symmetric with respect to a plane parallel to the axis and does not have rotational symmetry three or more times with respect to the axis. The periodic structure to be described.   An electromagnetic wave beam incident at a predetermined angle on a surface including any two basic translation vectors among the first to third basic translation vectors is propagated in a direction parallel to the surface, or with respect to the surface The periodic structure according to claim 1, wherein the periodic structure is propagated at an angle greater than a critical angle between the periodic structure and air.   The periodic structure according to claim 1, wherein the incident beam is branched into a plurality of beams propagating in parallel to each other.   The beam propagation direction according to claim 11 or the beam branching direction according to claim 12 is one of the direction of the first or second basic translation vector or the first to third basic translation vectors. The periodic structure according to claim 11 or 12, wherein the periodic structure is a direction in which one basic translation vector remaining on a surface including two basic translation vectors is projected.   By changing the incident angle or incident position of the incident beam or the wavelength of the incident beam, the intensity ratio of the two beams propagating in the opposite directions in the plane in claim 11 or the beam propagating in the same direction in claim 12 The periodic structure according to claim 11, wherein at least one of the intensity ratio and the branch interval changes.   The cross-sectional area or volume of the basic unit cell is the same as that of the periodic structure according to any one of claims 1 to 7, and one basic translation vector included in each is the same, and the type of medium in the unit structure Claimed at a wavelength corresponding to within ± 30% of the center value of energy corresponding to the wavelength of the antisymmetric mode of the periodic unit structure having the same composition ratio and the mirror-symmetric basic unit cell and unit structure Item 15. A periodic structure in which a refractive index or a dielectric constant periodically changes, which exhibits the beam propagation form described in any one of Items 11 to 14.   The periodic structure according to claim 1, wherein a pn junction or a pin junction exists in a medium in the unit structure of the periodic structure.   The periodic structure according to any one of claims 1 to 16, wherein the medium in the periodic structure contains a transparent conductor material, and the periodic structure has electrical conductivity.   The periodic structure according to claim 1, wherein the medium in the periodic structure contains a fluid and a solid.   The periodic structure according to any one of claims 1 to 18, wherein a part of the medium in the unit structure contains either a nonlinear optical material or a luminescent substance. A periodic structure according to any one of claims 1 to 19, and another periodic structure connected to the periodic structure and having a continuous medium and the periodic structure,
A composite period characterized in that a sum of first to third basic translation vectors constituting the periodic structure is different from a sum of first to third basic translation vectors constituting the other periodic structure. Structure.   A composite periodic structure comprising the periodic structure according to claim 1 and a uniform medium connected to the periodic structure. A method of manufacturing a periodic structure in which at least one of anisotropic deposition and anisotropic etching is used on a substrate on which the concavo-convex shape is formed with one-dimensional periodicity or two-dimensional periodicity. Because
The average incident direction of deposited particles or etched particles to the substrate is not perpendicular to the substrate surface,
The angle formed by the direction in which the incident direction is projected onto the substrate surface and the direction of the periodicity is in the range of 0 degrees to 45 degrees,
The manufacturing method of the periodic structure in any one of Claim 1 to 7.   A periodic structure or a composite periodic structure according to any one of claims 1 to 21, a light source, a polarizer, a reflective polarization separation element, a walk-off polarization separation element, a reflection means, a phase plate, a diffraction grating, and a scatterer And at least one selected from the group consisting of a spatial light modulator, an electrode, a photoreceptor and a light receiver. A parallel beam source, the periodic structure according to any one of claims 11 to 14, and a reflective polarization separation element,
A plane including any two basic translation vectors among the first to third basic translation vectors in the periodic structure and the reflective polarization separation element are parallel to each other;
The device according to claim 1, wherein a beam from the parallel beam source is incident on the periodic structure a plurality of times by the reflective polarization separation element. A laser light source, a spatial light modulator, a lens, a photoconductor, and the periodic structure according to claim 12;
By the periodic structure, the beam incident from the laser light source is branched into a plurality of beams propagating in the same direction and parallel to the incident light,
Transmitting or reflecting at least one of the plurality of branched beams by the spatial light modulator;
A device characterized in that a plurality of beams including at least a beam transmitted or reflected by the spatial light modulator are condensed by the lens at the same location on the photoconductor.

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