KR100791574B1 - Surface plasmon optic devices and radiating surface plasmon sources for photolithography - Google Patents

Abstract

Disclosed is a surface plasmon optical device comprising a dielectric substrate, a metal film formed on the dielectric substrate, and an arrangement of holes arranged periodically in the metal film, wherein light is emitted on the metal-air interface when light is irradiated onto the metal diffraction grating. do. Surface plasmon optics include surface plasmon generators, surface plasmon detectors, surface plasmon optics, etching devices and the like. Placing the metal diffraction gratings on a metal film with a well-defined interface allows for efficient reflection, separation and control of the propagation of surface plasmons. In addition, a radiating surface plasmon having a half period of lattice constant made in the air-metal (1,0) mode can allow its shape to be maintained at least several microns,

Description

SURFACE PLASMON OPTIC DEVICES AND RADIATING SURFACE PLASMON SOURCES FOR PHOTOLITHOGRAPHY}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for generating and regulating surface plasmons using periodic arrays of metal holes made in metal films and to photo-lithograpy devices using the same.

In general, a thick metal film is impermeable to incident light, and even when a hole is formed in the metal film, the light transmitted is significantly reduced if the size of the hole formed in the metal film is much smaller than the wavelength of the incident light. . However, it is known that even if the hole is smaller than the wavelength, the small hole is periodically arranged in the metal film, and the light is transmitted more efficiently when the period is about the size of the wavelength of the incident light. In addition, recent studies show that the spectral position and intensity of this transmission resonance phenomenon are well explained by conventional surface plasmon theory. However, the micro-domain's understanding of this phenomenon was lacking.

While studying the emission characteristics of the nano-regions in this arrangement, the inventors found a phenomenon in which the light of the polarization-controlled interference pattern is clearly emitted from the metal surface outside the hole mainly on the non-irradiated surface. This finding is in stark contrast to previous theoretical and experimental studies and the prediction of macro-regions where light is mainly emitted only in pores.

In addition, by the nano-domain experiments performed by changing the wavelength of the incident wave, polarization, and the size of the hole geometry formed in the metal film, surface plasmons made from these metal diffraction gratings are incoherent at distances of several tens of micrometers or more. It has been found that it can propagate while maintaining coherence.

In addition, it was found that by controlling the polarization and the wavelength of the incident light, the pattern of the light emitted from the air-metal interface can be controlled, and in particular, the square of the sine function can be made in the air-metal (1, 0) mode. The farther the light is distributed, the simpler the pattern becomes, and the more square the sine function is. The period of the sine function square is the same as the lattice constant, and the period of the original sine function before the square is twice the lattice constant. This mode is commonly called half wavelength mode because it has the form of lattice constant = wavelength / 2. The half-wave surface plasmon mode is capable of emitting light into the primitive field, unlike surface plasmons bound to the surface, which were previously considered. Therefore, the half-wavelength surface plasmon is named by the inventors as a radiating surface plasmon. Light emitting surface plasmons can be used for a new concept of lithography because the pattern is kept far.

A near-field study of the emission pattern of light generated at the metal-air interface when light is emitted to a metal diffraction grating having a constant cycle of hole arrays grown on a dielectric substrate has led to the following inventive ideas. First, these metal diffraction gratings can be used as surface plasmon detectors as well as surface plasmon generators having a well defined traveling direction. Second, placing these metal gratings on a metal film with a well-defined interface creates surface plasmon optics that can efficiently reflect, isolate, and control the propagation of surface plasmons. Third, by controlling the wavelength and polarization of light reflected on the metal diffraction grating, it is possible to control the emission pattern of light emitted from the air-metal interface. In particular, a radiating surface plasmon with a half-period lattice constant made in air-metal (1, 0) mode can keep its shape at least a few microns, which is used in the new concept of etching equipment. Can be. These inventions are expected to have a variety of applications when considering the reality that the role of the surface plasmon to increase the efficiency of the optical device is attracting attention.

Specifically,

It is an object of the present invention to provide the following devices using the above-described phenomena.

First, it provides a surface plasmon generator that can easily control the optical direction by using a metal diffraction grating having a periodic hole arrangement.

Second, using a metal diffraction grating having a periodic height change, to provide a detector that can efficiently detect the surface plasmon that proceeds.                 

Third, another metal diffraction grating is placed in the direction of the surface plasmon thus made to provide a surface plasmon splitter for separating the surface plasmon into two directions. This uses the property that the macroplasmic region can be moved with the coherence of surface plasmon.

Fourth, as another type of surface plasmon splitter, there is provided a surface plasmon splitter using a tunneling effect on a gap formed between metal films separated from each other.

Fifth, it provides a surface plasmon mirror using a metal surface having a specific angle and a moving direction of the surface plasmon. This uses the property that surface plasmons can only propagate on metal surfaces.

Sixth, it provides a surface plasmon control device that can control the propagation direction and speed of the surface plasmon using the electric field.

Seventhly, an optical etching apparatus using a half-wavelength light emitting surface plasmon mode is provided. This uses the property that half-wavelength light-emitting surface plasmon mode maintains its pattern even at a distance of several micrometers from the surface.

In order to achieve the above object, the configuration of the device according to the present invention is as follows.

First, the surface plasmon generator according to the present invention includes a dielectric substrate having an upper surface and a lower surface; A metal film having a first surface in contact with an upper surface of the dielectric substrate and a second surface facing the first surface; And a periodic through hole arrangement of the lattice structure formed in the metal film. When light enters the hole array from the lower surface side of the dielectric substrate, air / metal mode surface plasmons are excited on the second surface of the metal film of the hole array to emit stripe-shaped light. By injecting light having a wavelength and polarized light in accordance with the surface plasmon resonance conditions to the metal diffraction grating, it is possible to simply and efficiently generate a surface plasmon having a well-defined direction of travel.

Secondly, the surface plasmon detector according to the present invention is made by combining a local optical meter with a metal diffraction grating having a metal surface whose height is periodically changed in the direction of the surface plasmon.

Third, the surface plasmon splitter using the coherence of the surface plasmon according to the present invention is composed of a metal diffraction grating of a periodic hole array or a cylindrical array located in the advancing direction of the surface plasmon. The surface plasmons scattered in each hole or cylinder of the metal grating can be separated and proceed only in a specific direction to satisfy the condition of constructive interference. The surface plasmon splitter according to the present invention can efficiently separate the surface plasmon using the coherence of the surface plasmon.

Fourth, another surface plasmon splitter using tunneling of surface plasmons includes two metal interfaces separated from each other and a dielectric filled therebetween positioned at a specific angle and direction of the surface plasmon. At this time, the ratio of the surface plasmons separated by the distance between the two metal films and the dielectric constant of the dielectric filled therebetween can be adjusted, and the direction of the surface plasmons reflected by the angle of the metal boundary plane forming the surface plasmons Can be adjusted. By this configuration, the other surface plasmon splitter according to the present invention can easily control the separation ratio and the direction of progress of the surface plasmon.

Fifth, the surface plasmon mirror according to the present invention is composed of a metal boundary made to have a specific angle with the surface plasmon advancing direction and a dielectric placed outside. This uses the property that the surface plasmon can proceed only along the metal surface. The reflectance is determined by the dielectric constant of the dielectric material and the direction of the surface plasmon reflected by the angle of the metal interface leading to the advancing direction of the surface plasmon. By this configuration, the surface plasmon mirror according to the present invention can efficiently control the direction of the surface plasmon.

Sixth, the surface plasmon controller using the electric field is to control the propagation speed and the propagation direction of the surface plasmon by making electrodes at both ends of the surface plasmon. For example, a surface plasmon propagation path including a surface plasmon generator and a detector may be used to make electrodes at both ends and adjust the voltage applied therebetween to create or eliminate the flow of surface plasmon. This is based on the hypothesis that the propagation of surface plasmons can be controlled using an electric field. By such a configuration, the surface plasmon controller according to the present invention can efficiently control the surface plasmon by the electric field.

Seventhly, the optical etching apparatus according to the present invention is for forming a predetermined pattern on a photoresist-laminated substrate, the configuration of which is a photo-etching light source, and an optical type having holes periodically arranged in a metal film grown on a dielectric substrate. Each mask (metal grating) and array of photoresist-laminated substrates in which the pattern is to be made. At this time, since the light pattern emitted from the photoetch mask can be adjusted by changing the wavelength and polarization of the incident light, various patterns can be made with a single photoetch mask. There is also a technical advantage that the distance between the photoetch mask and the photoresist-laminated substrate can be significantly reduced since the pattern is maintained at least a few microns from the photoetch mask.

1 is a perspective view of a surface plasmon generator according to an embodiment of the present invention for explaining the principle of surface plasmon generation.

FIG. 2A shows an electron microscope image of a periodic arrangement of holes formed in the metal film of FIG. 1. FIG.

FIG. 2B is a diagram showing far-field transmission spectrum when light is incident on the surface plasmon generator of FIG. 1. FIG.

FIG. 2C is a view of an atomic force microscope (AFM) image when light is incident on the surface plasmon generator of FIG. 1. FIG.

FIG. 2D is a diagram of a near field transmission image at air-gold (0,1) resonance when light is incident on the surface plasmon generator of FIG. 1. FIG.

3A shows a near field transmission image at sapphire-silver (1,1) mode resonance.

FIG. 3B is a diagram of a near field transmission image at air-silver (1,0) mode resonance. FIG.

FIG. 3C shows an image at the edge of the periodic hole arrangement of the metal film in FIG. 3A. FIG.

FIG. 3D shows an image at the edge of the periodic hole arrangement of the metal film in FIG. 3B. FIG.

3E is a graph showing the intensity of emitted light in the horizontal direction in FIGS. 3C and 3D.

4A is a schematic representation of a propagation characteristic test of an air / silver (1,0) mode surface plasmon.

4B is an illustration of an atomic force microscope image at the edge of G1 in FIG. 4A.

4C is a diagram of the near field emission pattern for FIG. 4B.

FIG. 4D is a view of the near-field emission pattern when the polarization of incident light is rotated by 90 ° with respect to FIG. 4C. FIG.

4E is a graph showing the intensity of emitted light in the horizontal direction in FIGS. 4B and 4C.

5A is a schematic representation of a waveguiding experiment of air / sapphire (0,1) mode surface plasmon.

5B is an illustration of the atomic force microscope image of FIG. 5A.

5C is a diagram of the near-field emission pattern recorded simultaneously with the atomic force microscopy image of FIG. 5B.

6A is an emission pattern diagram of the air-gold (1,0) mode in the near field.

6b is an emission pattern diagram of the air-gold (1, 0) mode at a point 0.14 micrometers away from the surface.                 

6C is an emission pattern diagram of the air-gold (1, 0) mode at a point 1.2 micrometers from the surface.

6D is an emission pattern diagram of the air-gold (1, 0) mode at a point 2.2 microns away from the surface.

6E is a graph showing the total intensity of light emission, plotted as a function of distance from the surface.

Fig. 6F is a graph of Fig. 4C in the horizontal direction and plotting the intensity of light emission as a function of the distance in the horizontal direction.

FIG. 7A is an emission pattern diagram of the air / silver (1,0) mode in the near field. FIG.

FIG. 7B is an emission pattern diagram of the air-silver (1, 0) mode at a point 2.45 micrometers away from the surface,

7C is an emission pattern diagram of the sapphire-silver (1, 1) mode in the near field.

FIG. 7D is an emission pattern diagram of sapphire-silver (1, 1) mode at a point 0.68 micrometers away from the surface.

8 is a plan view of a surface plasmon splitter according to an embodiment of the present invention.

9 is a plan view of a surface plasmon splitter according to another embodiment of the present invention.

10 is a plan view of a surface plasmon mirror according to an embodiment of the present invention.

11 is a plan view of a surface plasmon controller using an electric field according to an embodiment of the present invention.

12A is a perspective view of a photolithography mask according to an embodiment of the invention.                 

12B is a perspective view of a patterned photoresist-laminated substrate using the photolithography mask of FIG. 12A.

Hereinafter, preferred embodiments of the present invention will be described after setting the phenomenon found by the present inventors with reference to the accompanying drawings.

With reference to FIGS. 1-5C, the generation, propagation and interference characteristics of the surface plasmons discovered by the experimenter are described.

1 is a perspective view of a surface plasmon generator 10 having a periodic hole arrangement of a lattice structure according to the present invention, the surface plasmon generator 10 comprising a dielectric substrate 12 having an upper surface and a lower surface; An optically thick metal film 11 formed on the upper surface of the dielectric substrate 12; And a periodic lattice structure of two-dimensional nanometer-sized holes 13 formed in the metal film 11. The metal film 11 is made of metal such as gold and silver and is deposited on the dielectric substrate 12 such as sapphire at a thickness of 300 nm. The array of cylindrical holes 13 is formed using a dry etching method after e-beam lithography (lithogarphy).

2A shows an electron microscope image of a typical metal film 11 having a hole arrangement structure. 2B shows the far field of the surface plasmon generator 10 formed in the metal film 11 made of gold having a thickness of 300 nm with a hole 13 having a diameter of 150 nm and a period of interval of 800 nm. -field) shows the transmission spectrum.

As shown in FIG. 2B, the surface plasmon resonance is clearly visible at both interfaces, i.e., at the interface of air / metal and sapphire / metal. In FIG. 2B, the 930 nm peak corresponds to an air / metal surface plasmon resonance with (m, n) = (1,0) or (0,1), and the 1200 nm peak corresponds to (m, n) = (1, 1) with sapphire / metal surface plasmon resonance.

In general, light cannot be directly coupled to surface plasmons because its dispersion curve does not intersect the surface plasmon dispersion curve. However, in the rectangular grating structure of the array of holes 13 with period p, photons are excited to surface plasmons by adding the lattice momentum G = 2π / p, which satisfies the following equation for momentum conservation:

Where m and n are integers, x and y are unit vectors for each direction, and Ksp and Kp are surface plasmons and quantum plane wavevectors, respectively.

For normal incidence, the resonant wavelength can be approximated by the following equation:

Where ε is the dielectric constant of air or sapphire.

Continuous wave titanium: A near-field scanning optical microscope in transmission mode in which a sapphire laser is incident on the sapphire / metal side, and a metal-coated fiber-tip with a hole of 100 nm diameter collects light on the air / metal side. Results of using (Near-field Scanning Optical Microscope: NSOM) are shown in FIGS. 2C and 2D. FIG. 2C is an atomic force microscope (AFM) image obtained using NSOM and FIG. 2D is a near-field view of resonance excitation of air / metal (0,1) mode surface plasmons with vertically polarized light (arrow direction). Show the image. Contrary to the expectation that light will mainly be emitted only in the pores, most emitted light is found in streaks perpendicular to the polarization direction of incident light on a flat metal surface. When the horizontally polarized light is incident, the stripe of transmitted light is perpendicular to the polarization direction of the incident light. In most cases, a noticeable emission outside the hole is found in the form of a stripe-like pattern.

In the above experiment, when the near-field image of the sapphire / metal mode is compared with the near-field image of the air / metal mode, the sapphire / metal (1,1) mode is mainly a hole 13, as shown in FIG. 3A. Although localized and symmetrical by the lattice Bragg vector along the (1,1) direction shown in the direction of the arrow in FIG. 3A is shown, no streaks of emitted light are visible. In contrast, in the air / metal (1,0) mode, as shown in FIG. 3B, stripes appear perpendicular to the arrow direction of FIG. 3B.

Also, at the edge of the grid pattern by the arrangement of the holes 13, the image differs significantly in the sapphire metal (1,1) mode and the air / metal (1,0) mode. As shown in FIG. 3C, the intensity of the sapphire / metal mode is drastically reduced at the edge of the grating, while the interference of the emission intensity for the air / metal (1,0) mode, as shown in FIGS. 3D and 3E. The rash lasts farther than a few micrometers.

In order to understand the image shown in FIGS. 2A-3E, it is important to consider the momentum conservation with respect to the coupling between surface plasmon and light. Due to the small pore size limitation, due to the different dielectric constants of air and sapphire, the mode that appears prominently at one interface is less likely to occur at the other interface. Thus, the air / metal mode plasmon is only weakly excited in the production process on the irradiated sapphire / metal side, but is remarkably generated on the air / metal side, and once the air / metal mode plasmon is excited by a periodic array of holes 13 By propagating along the surface and forming an interference pattern, it can be efficiently converted to light.

Thus, the emission pattern in this mode is determined by standing wave interference of surface plasmons with K _x = ± 2π m / p or K _y = ± 2π n / p, as shown in FIGS. 3B and 2D. Contrast in more than 95% of the near field image represents a very efficient wavevector-selection similar to the effect observed in the photon bandgap structure.

On the other hand, the sapphire / metal mode does not satisfy the momentum conservation once it is exposed at the air / metal interface. In addition, because of the large mismatch in velocity ("impedance") between these two interfaces, the sapphire / metal mode is shorter spatially at the air / metal interface, as is evident from the localized emission pattern of the sapphire / metal (1,1) mode. There is a tendency to have a coherence length. Thus, a strongly excited mode at one interface cannot effectively combine light at another interface.

The 'damping length' inferred by FIG. 3E (blue line) is on the order of 1 μm, but this distance cannot be treated as the propagation length of the surface plasmon. It merely represents the attenuation length of this surface plasmon pattern which is greatly affected by radiation losses. Non-radiative surface plasmons can propagate over much longer distances.

As shown above, at the air / metal interface, both sapphire / metal mode and air / metal mode appear, and the difference between these two modes is due to the difference of the dispersion curve, and the propagation of surface plasmon is better at the air / metal interface. do. Thus, it can be seen that the use of air / metal mode is more suitable than sapphire / metal mode to take advantage of the propagation characteristics of the surface plasmon excited by the hole arrangement.

The following experiment is for evaluating surface plasmon propagation characteristics, especially propagation length. As shown in FIG. 4A, incident light is incident on the first grating structure G2 to excite the plasmon and detect the near-field emission pattern in the second grating structure G1 separated by about 25 μm. The first and second grating structures are formed by periodic hole arrangements. 4B shows the AFM image at the edge of the second grating structure G1.

4C shows the near-field emission pattern at the edge of the second grating structure G1, and FIG. 4D shows the near-field emission pattern when the polarization of the incident light is rotated by 90 ° with respect to FIG. 4C. When the polarized light of the incident light is parallel to the line connecting the second grating structure G1 and the first grating structure G2, as shown in FIG. 4C, a strong signal is detected in the second grating structure G1. When the polarization direction of the incident light is rotated 90 degrees, as shown in Fig. 4D, no signal is detected in the second grating structure G1.

By this fact, it is clarified that the surface plasmon propagation direction generated in the first grating structure G2 is parallel to the polarization of the incident light, and the propagation length of the surface plasmon is about 10 μm. The value of the propagation length is similar to the propagation length in the metal film plane made of silver. In addition, the clear interference pattern shown in FIG. 4C shows that the surface plasmon produced in the first grating structure G2 propagates to the second grating structure G1 while maintaining coherence.

4E is a cross-sectional view of the horizontal direction in FIGS. 4B and 4C. As shown in FIG. 4E, the holes of the second grating structure G1 pattern appear essentially dark. This is because air / metal mode surface plasmons in the lattice structure G1 flow along the surface of the hole to the sapphire / metal interface, similar to the sapphire / metal mode surface plasmons appearing at the air / metal interface, as in FIG. 3A. Suggests that.

Next, efficient generation of surface plasmons that propagate over meso-region distances presents a new way to manipulate plasmon-based systems at the air / metal interface. This is explained by analyzing the emission characteristics of the surface plasmon in the waveguide structure composed of two adjacent hole arrays in which the detection section and the excitation section are 100 mu m apart, as shown in FIG. 5A. The wavelength to be excited is determined by air / silver (0,1) mode resonance with incident polarization parallel to the vertical direction. Strong light emission is detected inside the waveguide region and has an emission pattern similar to the excitation mode of a square waveguide. No emission is detected at the center of the array of holes, whereas weak emission components (center near the hole) are found at the array edge, which rapidly attenuates toward the interior of the array. Of course, near the excitation point, the light emission from the two lattice regions is much larger than that emitted from the flat metal surface between the two grating regions. However, the farther the distance from the excitation position, the greater the radiation loss for waves propagating into the lattice array, and these waves are greatly attenuated. In contrast, radiation losses for waves induced along connected metal strips are significantly reduced inside the waveguide structure. Therefore, the propagation length can be made larger as a result of forming the propagation path of the plasmon by the hole arrangement.

According to the above experimental results, even when the metal film is much thicker than the penetration depth, light is strongly emitted from the opaque metal surface. This surprising phenomenon is due to the generation, propagation and interference of surface plasmons that are strongly converted to light. It can be understood in terms of the balance between excitation and emission processes that the intensity of air / metal mode and sapphire / metal mode resonances in the far field transmission are about the same. The surface plasmon propagation direction is controlled by optical polarization, and the propagation distance can be made larger than several 10 m. These results suggest improvements in the efficiency of optical devices and optical devices through new applications of metal gratings such as surface plasmon sources and nano-optical surface plasmon detectors.

형태로 된다. 여기서 a_O는 격자 상수를 나타낸다. 이러한 사실은 E_x의 x-방향 주기가 2a_O인 빛방출표면플라즈 몬(radiating surface plasmon) 모드의 존재를 말해준다. 또 이모드의 패턴이 잘 유지된다는 특성은 새로운 광식각장치에 응용될 수 있다.]6 shows the change of the light emission pattern with metal surface and tip distance in air / gold (1, 0) mode. As shown in Figs. 6A-6D, it can be seen that the light emission pattern is well maintained up to 2.2 micrometers or more, and most of these signals are light emitted at a long distance rather than an evanescent wave near the surface. Quantitative analysis also confirms this fact. FIG. 6E shows the total amount of signal integrated over the xy-plane as a function of the distance z between the tip and the sample. It can be seen that more than half of the near field signal is light emitted to a far distance. In addition, since the Evernesant wave disappears within a few hundred nanometers, as the distance becomes larger, as shown in FIG. 6F, the light emission form becomes simpler and a small constant form is added.

Form. Where a _O represents a lattice constant. This fact indicates the presence of a radiating surface plasmon mode in which the x-direction period of E _x is 2a _O. The well-maintained pattern of this mode can be applied to new optical etching devices.]

However, FIG. 7 shows that light emitting surface plasmons are not produced at all surface plasmon resonance conditions. FIG. 7 compares the change of the light emission pattern according to the distance between the tip-sample of the air / silver (1, 0) mode and the sapphire / silver (1, 1) mode. As in FIG. 6, the air / silver (1, 0) mode maintains the pattern well over a long distance, but the sapphire / silver (1, 1) mode shows that the pattern disappears within several hundred nanometers.

Hereinafter, an application example of the surface plasmon device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 6 to 12B.

1 is a perspective view of a surface plasmon generator 10 according to an embodiment of the present invention. As shown in FIG. 1, the metal film 11 is formed on a dielectric substrate 12 such as sapphire, and a periodic array of holes 13 forming a lattice structure is formed in the metal film 11.

When light is incident on the array of holes 13 on the side of the dielectric substrate 12, as described above, the surface plasmon is excited by the array of holes 13 in the lattice structure, so that the surface plasmon generator 10 can be efficiently and easily surfaced. Generate plasmons.

8 is a plan view showing an application example of the surface plasmon splitter 20 using coherence according to an embodiment of the present invention. As shown in FIG. 8, the metal film 21 is formed in a branch shape on a dielectric substrate 22 such as sapphire, and has a first lattice structure 24 having an arrangement of periodic holes 23a serving as a surface plasmon generator. Is formed at one end of the metal film 21. The central portion of the metal film 21 has, for example, a shape separated into at least two or more branch shapes as shown in FIG. 8, and has a periodic hole arrangement or a cylindrical arrangement 23b serving as a surface plasmon splitter. The second grating structure 25 is formed. At each end separated in the shape of a branch from the center of the metal film 21, a third grating structure 26 and a fourth grating structure having periodic hole arrangements or cylindrical arrangements 23c and 23d serving as surface plasmon detectors ( 27) are formed respectively.

When horizontally polarized light is incident on the first lattice structure 24 of the metal film 21 from the dielectric substrate 22 side, since the surface plasmon is excited by the first lattice structure 24, the first lattice structure (24) acts as a source of surface plasmon. The surface plasmon generated in the first lattice structure 24 propagates along the surface of the metal film 21 to the second lattice structure 25 formed in the central portion of the metal film 21. Since the propagation characteristics of the surface plasmons have straightness, the surface plasmons generated from the first lattice structure 24 can propagate up to the second lattice structure 25, and the third lattice again by the second lattice structure 25. Propagated separately in the direction of structure 26 and fourth lattice structure 27. Here, the ratio of each separation of the surface plasmons may vary depending on the shape of the second lattice structure (25). Since the surface plasmons propagate to the third lattice structure 26 and the fourth lattice structure 27 and are converted into light by the lattice structures 26 and 27, the third lattice structure 26 and the fourth lattice structure ( 27) acts as a first detector and a second detector, respectively. In the present embodiment, two surface plasmon splitters are shown, but the present invention is not limited thereto.

9 is a plan view of the surface plasmon splitter 30 in another embodiment of the present invention. As shown in FIG. 9, the metal film 31 is formed in a T shape on the dielectric substrate 32 such as sapphire. The first lattice structure 34 of the arrangement of the periodic holes 33a serving as the plasmon generator is formed at one end of the metal film 31, and the arrangement of the periodic holes 33b of the second lattice structure 35 is formed. A cylindrical arrangement is formed at the other end of the metal film 31 opposite to one end of the metal film 31, and the arrangement of the periodic holes 33c or the cylindrical arrangement forming the third lattice structure 36 is the first lattice structure. And an intermediate end portion extending from the intermediate portion of the metal film 31 that connects the 34 and second lattice structures 35 to each other. For example, a gap 37 of 200 nm or less is formed diagonally in the middle portion of the metal film 31 extending between the first grating structure 24 and the second grating structure 25. This gap is filled with a dielectric having a predetermined dielectric constant.

When the horizontally polarized light is incident on the first grating structure 34 of the metal film 31 on the dielectric substrate 32 side, similarly to the surface plasmon splitter 20 of FIG. 8, the first grating structure 34 is provided. Since the surface plasmons are excited by the first lattice structure 34, the first lattice structure 34 functions as a generator of the surface plasmons. The surface plasmon generated in the first lattice structure 34 propagates along the surface of the metal film 31 to the gap 37 formed near the middle of the metal film 31. Some of the surface plasmons propagated from the first lattice structure 34 are reflected by the diagonally-shaped face to form a gap, and the direction of propagation to the third lattice structure 36 is changed, but the other part is affected by the tunneling effect. Thereby propagating through the gap 37 to the second lattice structure 35. Therefore, the surface plasmons propagate to the second lattice structure 35 and the third lattice structure 36 so that the surface plasmons are converted into light by the respective lattice structures 35 and 36, so that the second lattice structure 35 and The third grating structure 36 acts as a first detector and a second detector, respectively. At this time, the split ratio can be adjusted by adjusting the gap size between the two metal films and the dielectric constant of the dielectric filled therein, and the direction of the surface plasmon reflected can be changed by adjusting the angle of the metal interface forming the gap.

10 is a plan view of a surface plasmon mirror 40 according to an embodiment of the present invention. As shown in FIG. 10, the metal film 41 is formed in a "-" shape on the dielectric substrate 42 such as sapphire. An array of periodic holes 43a constituting the first grating structure 44 is formed at one end of the metal film 41, and the arrangement of periodic holes 43b constituting the second grating structure 45 is the first grating structure. A portion formed at the other end of the metal film 41 perpendicular to the 44 and intersecting the first grating structure 44 and the second grating structure 45 has a shape cut diagonally.

The surface plasmon mirror 40 of FIG. 10 has the same shape as the surface plasmon splitter 30 of FIG. 9 except for the metal film on which the second lattice structure 35 is formed in the surface plasmon splitter 30 of FIG. 9. When horizontally polarized light is incident on the first grating structure 44 from the dielectric substrate 42 side, since the surface plasmon is excited by the first grating structure 44, the first grating structure 44 is the surface plasmon. Acts as a generator of. When the surface plasmon generated in the first lattice structure 44 reaches a diagonally cut shape formed in the middle portion of the metal film 41 along the surface of the metal film 41, the surface plasmon is formed in the diagonal shape of the metal film 41. Reflected to change the propagation direction to the second grating structure 45. The surface plasmon propagated up to the second grating structure 45 is converted into light by the grating structure 45, and thus the second grating structure 45 acts as a detector.

11 is a plan view of the surface plasmon controller 50 according to an embodiment of the present invention. As shown in FIG. 11, the surface plasmon controller 50 includes a dielectric substrate 52 such as sapphire; A rod-shaped metal film 51 formed on the dielectric substrate 52; And a pair of electrodes 56 and 57 formed at both ends of the metal film 51. An array of periodic holes 53a constituting the first grating structure 54 is formed at one end of the metal film 51, and the arrangement of periodic holes 53b constituting the second grating structure 55 is formed of the first grating structure ( It is formed at the other end of the metal film 51 opposite to 54.

When the horizontally polarized light is incident on the first grating structure 54 from the dielectric 52 side, the surface grating is excited by the first grating structure 54, so that the first grating structure 54 is formed of the surface plasmon. Act as a source. The surface plasmon generated in the first lattice structure 54 propagates along the surface of the metal film 51 to the second lattice structure 55. The surface plasmon propagated up to the second grating structure 55 is converted into stripe-shaped light perpendicular to the polarization direction of the incident light by the second grating structure 55, so that the second grating structure 55 acts as a detector. do.

At this time, an electric field is applied to the pair of electrodes 56 and 57 to control the surface plasmon propagating from the first lattice structure 54 to the second lattice structure 55 along the surface of the metal film 51. Can be. For example, when a positive voltage is applied to the electrode 56 and a negative voltage is applied to the electrode 57, the direction of the electric field due to the voltage applied to the pair of electrodes 56 and 57 is the surface plasmon. Since it is the same as the propagation direction of, more surface plasmons propagate to the second lattice structure 55, and the stripe-shaped light perpendicular to the polarization direction of the incident light is emitted. On the contrary, when a negative voltage is applied to the electrode 56 and a positive voltage is applied to the electrode 57, the direction of the electric field due to the voltage applied to the pair of electrodes 56 and 57 is determined by the surface plasmon. Since the opposite direction of propagation interferes with the propagation of plasmon, light is not emitted from the second grating structure 55.

In the present embodiment, control using an electric field has been described, but instead of using an electrode, as described above, since the propagation direction of the surface plasmon is parallel to the polarization direction of the incident light, the surface plasmon is changed by changing the polarization direction of the incident light. You can also control.

12A is a perspective view of a photoetch mask according to an embodiment of the present invention, and FIG. 12B is a perspective view of a photoresist-laminated substrate having a pattern formed using the photoetch mask of FIG. 12A. As shown in FIG. 12A, a metal film 62 is formed on a dielectric substrate 61 such as sapphire, and holes are formed in the metal film 62 having a periodic arrangement. At this time, the pattern to be formed on the photoresist-laminated substrate 64 is determined according to the wavelength and polarization of the incident light. In particular, when light is incident from the dielectric substrate 61 and the wavelength is set to the air / metal surface plasmon resonance condition, the light of the stripe shape is emitted when the polarization of the light is adjusted. The emitted light shows a complex pattern near the metal lattice, and when the distance is several hundred nm away, it becomes a simple sine wave and the sine wave is maintained up to several tens of micrometers. Therefore, when the photoresist-laminated substrate 64 is disposed several micrometers away from the metal film 62, the sinusoidal emission light is irradiated onto the photoresist-laminated substrate 64 to form clean lines. do.

Although the present invention has shown and described preferred embodiments of the surface plasmon device, the present invention is not limited to the above-described embodiments. For example, the surface plasmon device can be used to increase the efficiency of the optical device and the optical device. Will be understood by.

According to the present invention, a metal film is formed on a dielectric substrate and a periodic array of holes forming a lattice structure is formed in the metal film so that when the light is incident on the array of holes on the dielectric substrate, the surface plasmon is excited on the metal film side of the hole array. As a result, it is possible to easily and effectively produce the surface plasmon proceeding in a specific direction. In addition, the periodic hole arrangement or cylinder arrangement made in the metal film is combined with a local photodetector to serve as a surface plasmon detector. According to the present invention, the surface plasmon splitter and the surface plasmon mirror can be provided to effectively control the propagation of the surface plasmon. These inventions will play an important role in devices where surface plasmons are used to increase the efficiency of optical devices. In addition, in the present invention, the light produced by the surface plasmon generator maintains the pattern up to several micrometers under certain conditions, and the pattern can be changed by adjusting the wavelength and polarization of the incident light. An optical etching device can be provided.

Claims (14)

A dielectric substrate having a first surface and a second surface; A metal film having a first surface and a second surface, the metal film having a first surface of the metal film substantially in contact with a second surface of the dielectric; And A periodic arrangement of nanometer-sized holes penetrating the first surface of the metal film and the second surface of the metal film, Surface plasmon generator, wherein light is incident on the periodic hole arrangement on the first surface side of the dielectric substrate, and air / metal mode surface plasmons are excited on the second surface of the metal film to emit striped light. . The surface plasmon generator according to claim 1, wherein the dielectric substrate is a sapphire substrate. A dielectric substrate having a first surface and a second surface; 1. An optically thick metal film having a first surface and a second surface, the first surface of the metal film being substantially in contact with the second surface of the dielectric and further comprising one side, an intermediate portion, and the other side. The side portion extends from the intermediate portion and is divided into at least two portions; A periodic first arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film, formed on one side of the metal film; A second periodic arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film formed in the middle of the metal film; And And periodic third arrays of nanometer-sized holes penetrating the first and second surfaces of the metal film, each formed in at least two or more divided portions of the other side, Light polarized in the same direction from the first hole array to the second hole array is incident on the first hole array of the metal film on the first surface side of the dielectric substrate, and air on the second surface of the metal film. And / or a metal mode surface plasmon is excited and propagated along the metal film to the second hole array, and the surface plasmon propagated by the propagated surface plasmon to the second hole array is divided in the second hole array, and the third A surface plasmon splitter, each propagating to arrays, wherein light is emitted from each of said third arrays. 4. The surface plasmon splitter according to claim 3, wherein said dielectric substrate is a sapphire substrate. A dielectric substrate having a first surface and a second surface; An optically thick metal film having a first surface and a second surface, the first surface of the metal film being substantially in contact with the second surface of the dielectric and further comprising a horizontal portion and a vertical portion divided into one side and the other side, A “T” shaped metal film extending from one side of the horizontal portion to the vertical portion; A periodic first hole arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film, formed on one side of the horizontal portion of the metal film; A periodic second hole arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film, formed on the other side of the horizontal portion of the metal film; A periodic third hole arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film formed in the vertical portion of the metal film; And A diagonal gap formed at a predetermined interval between a horizontal portion on one side of the metal film including the first hole array and a horizontal portion on the other side of the metal film including the second hole array; The light polarized in the same direction from the first hole array to the second hole array is incident on the first surface side of the dielectric substrate into the first hole array of the metal film, and the metal of the first hole array An air / metal mode surface plasmon is excited on the second surface of the film and propagates along the metal film, a portion of the propagated surface plasmon is reflected by the gap forming metal film to emit light in the third hole arrangement, And another portion of said propagated surface plasmon tunneling said gap so that light is emitted from said second hole arrangement. 6. The surface plasmon splitter according to claim 5, wherein said dielectric substrate is a sapphire substrate. A dielectric substrate having a first surface and a second surface; An optically thick metal film having a first surface and a second surface, wherein the first surface of the metal film is substantially in contact with the second surface of the dielectric, and has one end of the horizontal portion and one of the ends of the horizontal portion. A vertical portion extending from the end, wherein the connecting portion of the horizontal portion and the vertical portion of the metal film has a diagonal shape; A periodic first hole arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film formed in the horizontal portion of the metal film; A periodic second hole arrangement of nanometer-sized holes perpendicular to the first hole arrangement and penetrating the first and second surfaces of the metal film formed at a vertical portion of the metal film; And Light polarized in the same direction as the horizontal direction of the horizontal portion of the metal film is incident on the first hole array at the first surface side of the dielectric substrate, and is in the air / metal mode on the second surface of the metal film of the first hole array. Surface plasmons are excited and propagated along the horizontal direction of the metal film, the propagated surface plasmons are reflected in the diagonal portion to emit light in the second hole arrangement. 8. The surface plasmon mirror of claim 7, wherein the dielectric substrate is a sapphire substrate. A dielectric substrate having a first surface and a second surface; An optically thick metal film having a first surface and a second surface, the metal film formed in a rod shape, the first surface of the metal film being substantially in contact with the second surface of the dielectric; A periodic first hole arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film formed on one side of the metal film; A periodic second hole arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film formed on the other side of the metal film opposite the first hole arrangement, Of the metal film of the first hole array when light polarized in the same direction from the first hole array to the second hole array is incident on the first hole array toward the first surface of the dielectric substrate; An air / metal mode surface plasmon is excited on the second surface and propagates along the metal film to the second array of holes, in which the stripe-shaped light is emitted in the second array of holes, in a direction rotated 90 ° to the polarization. The surface plasmon controller, characterized in that the light is not emitted in the second hole array when the polarized light is incident. 10. The surface plasmon controller of claim 9, wherein the dielectric substrate is a sapphire substrate. A dielectric substrate having a first surface and a second surface; An optically thick metal film having a first surface and a second surface, the metal film formed in a rod shape, the first surface of the metal film being substantially in contact with the second surface of the dielectric; A periodic first hole arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film formed on one side of the metal film; A periodic second hole arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film formed on the other side of the metal film opposite the first hole arrangement, A first electrode formed at an end of the metal film including the first hole arrangement; And A second electrode formed at an end of said metal film comprising said second hole arrangement, Of the metal film of the first hole array when light polarized in the same direction from the first hole array to the second hole array is incident on the first hole array toward the first surface of the dielectric substrate; In the second hole arrangement, when an air / metal mode surface plasmon is excited on the second surface and propagates along the metal film, a positive electrode is applied to the first electrode, and a negative voltage is applied to the second electrode. And when light is emitted, a negative voltage is applied to the first electrode, and a positive voltage is applied to the second electrode, no light is emitted from the second hole array. 12. The surface plasmon controller of claim 11, wherein the dielectric substrate is a sapphire substrate. A photolithography mask for forming a predetermined pattern on a photoresist-laminated substrate, A dielectric substrate having a first surface and a second surface; An optically thick metal film having a first surface and a second surface, the metal film having a first surface of the metal film substantially in contact with a second surface of the dielectric; And A periodic hole arrangement of nanometer-sized holes penetrating the first and second surfaces of the metal film, When light is incident on the array of holes on the first surface side of the dielectric substrate, an air / metal mode surface plasmon is excited on the second surface of the metal film of the array of holes and can be controlled by the wavelength and polarization of the incident light. Light is emitted, and the emitted light is irradiated to form a corresponding pattern on the photoresist-laminated substrate. The photolithography mask of claim 13, wherein the dielectric substrate is a sapphire substrate.

Images