JP2007121268A - Optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical system of a reduced noise having a long WD, and an optical apparatus such as a near-field microscope using the same. <P>SOLUTION: The optical apparatus includes with a light source 303, a negative refractive-index medium 301 of an optical element formed of a medium indicating a negative refractive index, an opening 907 for light detection or illumination, or a probe 904, and the opening 907 or the probe 904 is arranged in an area where the intensity of an evanescent wave emitted from an object 307 is higher than an evanescent wave in the object 307. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical system and an optical apparatus using the same.

  Optical systems such as an optical element, a microscope, a lithography optical system, and an optical disk optical system, and optical apparatuses using them are as follows (for example, Non-Patent Document 1, Non-Patent Document 2, Non-Patent Document). 3, see Patent Document 1 and Patent Document 2).

Introduction to near-field nanophotonics, P7 to P14, P74 to 75, P86 to P87, Optronics, published on April 25, 2000 In addition to the above, the following documents are related. J.B.Pendry Phys. Rev. Lett., Vol85, 18 (2000) 3966-3969 M. Notomi Phy.Rev.B.Vol 62 (2000) 10696 US 2003/0227415 A1 US 2002/0175693 A1 Sato / Kawakami Optronics July 2001 issue 197 pages Published by Optronics

  FIG. 12 is a diagram showing a configuration of a reflection mode of a conventional near-field microscope 901 (see Non-Patent Document 1). Light emitted from the light source 303 enters the optical fiber probe 904 through the half prism 902 and the lens 903 which is an optical element made of a material having a positive refractive index. The optical fiber probe 904 is obtained by applying a metal coating 906 to a glass fiber 905 composed of a core 910 and a clad 909.

  Light entering the optical fiber probe 904 exits from the opening 907 and strikes an object 307 as an observation target. Light including the evanescent wave reflected by the object 307 passes through the opening 907, is reflected by the half prism 902, enters the photomultiplier 908 as a light receiving element, and is converted into an electric signal.

  An image signal is obtained from an electrical signal by scanning the optical fiber probe 904 mainly in the lateral direction.

  Here, the distance between the opening 907 and the object 307 is defined as WD (Working Distance). The size of the opening 907 is several nanometers to several tens of nanometers.

  Conventionally, in various optical systems for forming an image (forming an object image) or forming a light spot, the resolution is limited due to diffraction caused by the wave nature of the light or electromagnetic wave used. was there. Therefore, the above-mentioned Non-Patent Document 2 discloses the use of a negative refractive index medium as a technique for realizing such imaging that exceeds the diffraction limit.

FIG. 10 is an explanatory diagram showing an image formed by the flat plate 380 formed of the negative refractive index medium 301. However,
t0 ... Distance between the object point and the left side of the flat plate 380 t0 '... Distance between the image point and the right side of the flat plate 380 t ... Thickness of the flat plate 380 i ... Incident angle r ... Refraction angle ns ...

  The refractive index around the flat plate 380 is n0, and n0 = 1 in the case of a vacuum. FIG. 10 shows the case where n0 = 1 and ns = -1.

  In this application, the term “light” includes electromagnetic waves.

The arrow indicates the emitted light component of the light emitted from the object. According to Non-Patent Document 2, the law of refraction holds. N0 sin i = ns sin r Equation (101)
If n0 = 1 and ns = -1, then r = -i Equation (102)
It becomes. Therefore,
t0 + t0 '= t (103)
The light of the radiated light component is imaged as an image point at t0 ′ that satisfies the above.

On the other hand, the evanescent wave emitted from the object point has the same intensity as the object point at t0 ′ satisfying the equation (103). Since all the light emitted from the object gathers at the image point, imaging that exceeds the diffraction limit is realized. This is called complete imaging. Even if the periphery of the negative refractive index medium 301 is not a vacuum, the complete image formation is performed using the equation (103) and ns = -n0 (formula (104)).
It is known from Non-Patent Document 2 that it is realized if the above is satisfied.

  At this time, as shown in FIG. 11, the intensity of the evanescent wave attenuates with an exponential function as it advances from the object point in the z direction, and is amplified with an exponential function inside the negative refractive index medium 301, and the negative refractive index medium 301. After exiting, it decays again with an exponential function.

  However, in the example of FIG. 12, it is necessary to bring the opening 907 close to the object 307 to several tens of nanometers in order to detect a weak evanescent wave, the distance WD is small, the type of the object is limited, and the object may be damaged There were disadvantages such as. Further, since the evanescent wave is weak, there is a drawback that noise easily enters the image.

  In view of this point, the present invention provides, for example, an optical system having a long WD and low noise, and an optical apparatus such as a near-field microscope using the optical system.

  In order to solve the above-described problems and achieve the object, according to the first aspect of the present invention, a light source, an optical element formed of a medium exhibiting negative refraction, an opening member or a probe for light detection or illumination And an aperture member or a probe is arranged in a region where the intensity of the evanescent wave emitted from the object is larger than the intensity of the evanescent wave in the object.

  According to the second aspect of the present invention, the light source, the optical element formed of a medium exhibiting negative refraction, and the opening member or probe for light detection or illumination are provided and detected by the opening member or probe. When the converted light is converted into an electrical signal, an optical device can be provided that takes into account the amplification factor of the evanescent wave by the optical element formed of a medium exhibiting negative refraction.

  According to the third aspect of the present invention, the light source, the optical element formed of a medium exhibiting negative refraction, and a minute object for light scattering, the intensity of the evanescent wave emitted from the object is It is possible to provide an optical device in which a minute object for light scattering is arranged in a region larger than the intensity of the evanescent wave in the object.

  According to the present invention, it is possible to provide an optical system having a long WD and less noise and an optical apparatus such as a near-field microscope using the optical system.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a near-field microscope 401 using a negative refractive index medium 301 according to an embodiment of the present invention. The operation is as follows.

  Light emitted from the light source 303 such as a mercury lamp, laser, or semiconductor laser passes through the illumination lens 890 and the slide glass 891 to illuminate the object 307.

  Light passing through the object 307 passes through the negative refractive index medium 301 and enters the optical fiber probe 904. The optical fiber probe 904 is obtained by applying a metal coating 906 to a glass fiber 905. The light including the evanescent wave scattered by the object 307 passes through the opening 907, passes through the optical fiber probe 904 and the lens 903, is reflected by the prism 892, enters the photomultiplier 908, and is converted into an electrical signal.

  The negative refractive index medium 301 and the optical fiber probe 904 are integrally scanned in the lateral direction, or the negative refractive index medium 301 is fixed to the object 307, and the optical fiber probe 904 is scanned alone to obtain an image signal from the electrical signal. .

  Conversion from an electrical signal to an image signal is performed by a signal processing device 894. The image signal is processed by the computer 895, and an image is displayed on the television monitor 896. The distance between the object side surface 312 of the negative refractive index medium 301 and the object 307 is t0. In FIG. 1, t0 is equal to WD. The distance between the upper surface 310 of the negative refractive index medium 301 and the opening 907 is s.

In the present embodiment, the position of the opening 907 is very close to the upper surface 310,
s <t-t0 Formula (19)
t−t0> 0 Formula (20)
Meet.

  Therefore, the object 307 and the opening 907 are not in a complete imaging relationship represented by the equation (103). In this way, as shown in FIG. 11, the intensity E of the evanescent wave becomes stronger than the intensity E0 of the evanescent wave on the object surface, and an image signal with less noise can be obtained. Further, since the value of t0 can be arbitrarily selected within a range that satisfies the equations (19) and (20), a long WD can be realized.

  A point Q in FIG. 11 indicates the intensity E (t 0 + t + s) of the evanescent wave at the position of the opening 907. The z coordinate of the opening 907 is t0 + t + s.

  On the other hand, since the amplification factor of the intensity of the evanescent wave varies depending on the spatial frequency component of the object 307, image processing by the computer 895 is required.

  Hereinafter, this image processing will be described in detail. The radiated light component from the object 307 is ignored because the opening 907 is close to the upper surface 310 of the negative refractive index medium 301 and is weaker than the evanescent wave.

  The coordinate system is taken as shown in FIG. The x-axis passes through point 0, is perpendicular to the paper surface, and the direction toward the back surface is positive.

Various quantities are defined as follows.
898 ... plane that scans the opening 907 and is perpendicular to the z-axis F (x, y) ... light intensity distribution of the object 307 f (k _x , k _y ) ... Fourier transform of the light intensity distribution of the object 307 G (x Y) ... Evanescent light intensity distribution on detection surface 898 g (k _x , k _y ) ... Fourier transform of evanescent light intensity distribution on detection surface 898 k _x ... x component of wave number of spatial frequency of object light on object surface k _y ... y component of the wave number of the spatial frequency of the object light on the object plane n0 ... refractive index of the medium between the object 307 and the object side surface 312 ns ... refractive index of the negative refractive index medium 301 n1 ... the upper surface 310 and the detection surface 898 Refractive index of the medium between

  Here, G can be obtained by scanning the optical fiber probe 904. F is the amount you want to find. t0, t, s are known quantities that can be measured.

ここで、ｃは真空中の光速度、
ωは用いる光の振動数に２πを掛けたものである。

Where c is the speed of light in vacuum,
ω is obtained by multiplying the frequency of light used by 2π.

Then, according to Non-Patent Document 2,
g = f · exp (−k _z t0) · exp (+ k _z 't) · exp (−k _z ″ s)
... Formula (23)
Is obtained.

Therefore,
f = g · exp (+ k _z t0) · exp (−k _z 't) · exp (+ k _z ″ s)
... Formula (24)
Thus, the Fourier transform of the object light intensity distribution is obtained. Therefore, if f is subjected to inverse Fourier transform, the desired F can be obtained.

As described above, the calculation (image processing) after Expression (21) is performed by the computer 895. In addition, this image processing may not be performed, for example, when quantitativeness is not required for the imaging result of the object.

In this embodiment, the following parameters are used.
t0 = 200 nm
t = 1000 nm
s = 30 nm
n0 = 1.00028 (refractive index of air)
ns = −1.00028
n1 = 1.00028 (refractive index of air)
λ = 500nm

Note that λ is the wavelength of light used. In the case of visible light, λ is 380 to 700 nm.
So far,
ns = -n0 = -n1 Formula (24-2)
Met.

However,
ns ≠ −n0 Expression (25)
However, the effects of noise reduction and WD increase can be realized to some extent. Even in the case of Expression (25), Expression (21) to Expression (24) can be applied.

In this case, equation (19), on behalf of the (20), at least one set of _k x, with respect to _{k y,
exp (-k z t0) · exp} (+ k z 't) · exp (-k z "s)> 1
... Formula (20-2)
It is good to meet.

Examples of parameters in a near-field microscope according to another embodiment of the present invention are listed below.
t0 = 400 nm
t = 1500 nm
s = 50 nm
n0 = 1.33 (refractive index of water (H ₂ O))
ns = -2
n1 = 1.00028 (refractive index of air)
λ = 650 nm

Examples of parameters in a near-field microscope according to still another embodiment of the present invention are listed below.
t0 = 100 nm
t = 200 nm
s = 20 nm
n0 = 1.0 (refractive index of vacuum)
ns = -3
n1 = 1.0
λ = 800nm

As is common to the present application, the smaller the value of s, the higher the amplification factor of the evanescent wave,
s <300λ Formula (25-1)
Or s <30λ ... Formula (25-2)
It is good to meet.
s <3λ Formula (25-3)
It is even better to meet.
s <λ / 3 Formula (25-4)
Better to meet.

Further, t0 does not become too small before the evanescent wave is amplified by the negative refractive index medium 301.
t0 <500λ Formula (26)
It is good to do.
t0 <20λ Formula (26-2)
And that's even better.
t0 <λ Formula (26-3)
Even better.

  FIG. 3 is a diagram showing the configuration of the reflection mode of the near-field microscope 401-2 using the negative refractive index medium 301 according to an embodiment of the present invention. The operation is as follows.

  Light emitted from a light source 303 such as a mercury lamp, a laser, or a semiconductor laser passes through a half prism 902 and a lens 903 and enters an optical fiber probe 904. The optical fiber probe 904 is obtained by applying a metal coating 906 to a glass fiber 905.

  Light entering the optical fiber probe 904 exits from the opening 907 and passes through the negative refractive index medium 301 and strikes the object 307. The light including the evanescent wave reflected by the object 307 passes through the opening 907, passes through the glass fiber 905, is reflected by the half prism 902, enters the photomultiplier 908, and is converted into an electrical signal.

  The negative refractive index medium 301 and the optical fiber probe 904 are integrally scanned in the lateral direction, or the negative refractive index medium 301 is fixed to the object 307, and the optical fiber probe 904 is scanned alone to obtain an image signal from the electrical signal. . In this example, light passes through the negative refractive index medium 301 twice in the opposite direction.

  The signal processing after the photomultiplier 908 is the same as the example of FIG. There is a merit that observation is possible even when the object 307 is opaque because of the optical system in the reflection mode.

  FIG. 4 shows another embodiment of the present invention, which shows a transmission type near-field microscope 315 using a negative refractive index medium 301. In FIG. 4, only the vicinity of the illumination optical system 316 and the negative refractive index medium 301 is shown enlarged.

  The light from the light source 303 enters the prism 317 and enters the surface 318 of the prism 317 on the object 314 side at an angle for total reflection. Therefore, the object 314 as the observation target is illuminated with an evanescent wave. Scattered light from the object 314 is refracted by the negative refractive index medium 301 and enters the opening 907. Then, it is observed by being scanned by the optical fiber probe 904. The signal processing after the photomultiplier 908 is the same as in the example of FIG.

  Expressions (19), (20), (20-2), and (21) to (24) are similarly applied in this example. According to this configuration, noise due to illumination light can be reduced.

  FIG. 5 shows another embodiment of the present invention, which is an atomic force microscope type near-field microscope 912 using a cantilever 911 as a light scattering minute object. A microsphere may be used instead of the cantilever 911. The configuration of the illumination optical system 316 is the same as that in FIG.

  Light emitted from the object 314 is scattered by the tip of the cantilever 911. The scattered light at this time enters the lens 306, enters a photomultiplier (not shown), and is converted into an electrical signal. The electrical signal processing is the same as in the example of FIG.

  An object image is obtained by scanning the cantilever 911 with the negative refractive index medium 301 integrally or separately with respect to the object 314. The advantage is that the working distance (WD) can be made longer than that of a conventional atomic force microscope type near-field microscope. Equations (19), (20), (20-2), (21)-(24) apply equally to this example.

  FIG. 6 shows a near-field microscope 918 in which a plate 916 (opening member) having a pinhole 915 and a negative refractive index medium 301 are used in combination. The configuration of the illumination optical system 316 is the same as that in FIG.

  The pinhole 915 plays the same role as the opening 907 in the example of FIG. 4, and the plate 916 is mainly used with respect to the object 314 together with the negative refractive index medium 301 or separately from the negative refractive index medium 301. An image is obtained by scanning in the horizontal direction. The size of the pinhole 915 is several nm to several tens of nm.

  Light emitted from the object 314 passes through the pinhole 915, enters the photomultiplier 908, and is converted into an electrical signal. Then, an image is obtained by image processing. The signal processing after the photomultiplier 908 is the same as in the example of FIG. Expressions (19), (20), (20-2), and (21) to (24) are similarly applied in this example.

  In addition, although it is about the shape of the negative refractive index medium 301, in the embodiment of FIGS. 1, 3, 4, 4, and 6, the shape of the negative refractive index medium 301 may not be a parallel plate.

  As shown in FIG. 7, a negative refractive index medium lens 301-3 formed of a negative refractive index medium and having a convex surface on the object side may be used. In FIG. 7, the negative refractive index medium lens 301-3 is a curved surface having a flat surface on one side and a convex surface on the other surface.

  The shape of the curved surface of the negative refractive index medium lens 301-3 may be a spherical surface, an aspherical surface, a free curved surface, a rotationally asymmetric surface, an extended curved surface, or the like.

  The refractive index of the negative refractive index medium lens 301-3 may not be -1.

The following is a description common to the present invention. A specific material of the negative refractive index medium 301 is a photonic crystal. FIG. 8 shows a first specific example of the photonic crystal 340, and FIG. 9 shows a second specific example of the photonic crystal 340. As shown in FIGS. 8 and 9, the photonic crystal 340 is a substance having a periodic structure of about λ to several tens of 1λ, and is formed by lithography or the like. The material is a dielectric such as a synthetic resin such as SiO ₂ , TiO ₂ , acrylic, polycarbonate, or GaAs. Here, λ is the wavelength of light used. The values of the repetitive cycles Sx, Sy, Sz in the X, Y, and Z directions in the figure have a value of about λ to several tens of 1λ. It is known that a negative refractive index can be realized in the vicinity of the band edge of a photonic crystal (see Non-Patent Document 3). The Z direction in the figure is preferably the optical axis of the optical system.

  The Z axis is the direction of the axis having the best rotational symmetry of the photonic crystal.

  Sx, Sy, and Sz desirably satisfy any of the following formulas.

λ / 10 <Sx <λ Formula (5-1)
λ / 10 <Sy <λ Formula (5-2)
λ / 10 <Sz <λ Formula (5-3)
If the values of Sx, Sy, Sz exceed the upper limit or fall below the lower limit, they will not function as a photonic crystal.

Depending on the application,
λ / 30 <Sx <4λ Formula (5-4)
λ / 30 <Sy <4λ Formula (5-5)
λ / 30 <Sz <4λ Formula (5-6)
Any one of the above may be satisfied.

  As for the negative refractive index medium, when the relative dielectric constant ε of the medium is negative and the relative permeability μ of the medium is negative, the refractive index of the medium is

It is known to become.
The negative refractive index medium may be a material exhibiting negative refraction, a material exhibiting negative refraction approximately, such as a thin film of silver, gold, copper, etc., a material exhibiting a negative refractive index in a specific polarization direction, or a helical structure. For example, a material having a negative dielectric constant ε or magnetic permeability μ, for example, −1 may be used.

  Further, the negative refractive index medium may be referred to as a left handed material. In this application, these negative refractive index media, left-handed materials, substances that exhibit negative refraction approximately, substances that exhibit a negative refractive index in a specific polarization direction, substances that have a helical structure, dielectric constant ε or magnetic permeability μ are negative. All of these materials are called a medium exhibiting negative refraction. Substances exhibiting complete imaging are also included in the medium exhibiting negative refraction. Further, when the dielectric constant ε or the magnetic permeability μ is a negative material, the following formula is preferably satisfied.

ε ′ = ε / εc (formula (5-6-1))
μ ′ = μ / μc Formula (5-6-2)
Then, ε ′ and μ ′ are defined.
However,
εc is the dielectric constant of the medium in the portion t0 μc is the magnetic permeability of the medium in the portion t0.

At this time,
−1.2 <ε ′ <− 0.8 Formula (5-7)
It is good to satisfy. Depending on the application,
−1.6 <ε ′ <− 0.5 Formula (5-8)
But you can. In the case of a thin film of a substance having a magnetic permeability of approximately −1, ε ′ in the expressions (5-7) and (5-8) may be replaced with μ ′. In addition, when the term “complete imaging” is used in the present application, it includes a case where 100% complete imaging is not performed. For example, the case where the imaging performance is several times the diffraction limit is included in the complete imaging. The case where the imaging performance is improved by several tens of percent from the diffraction limit is also included in complete imaging.

  The wavelength of light to be used is not limited to those described in the embodiment, and a continuous spectrum light source, a white light source, a sum of a plurality of monochromatic lights, a low coherence light source such as a super luminescent diode, or the like may be used. .

  The wavelength is preferably 0.1 μm to 3 μm because it can be transmitted in the air and the light source is easily available. Visible wavelengths are easier to use.

  It is even better if the wavelength is 0.6 μm or less because the resolution is easily improved.

If WD can be secured to some extent, t0 should be as small as possible, but t0 ≤ 10000λ (18-1)
Or
t0 ≦ 1000λ Formula (18-2)
But some products are acceptable.

t0 ≦ 100λ (18-3)
If so, the evanescent wave can be used effectively.

t0 ≤ 5λ (18-4)
Even better.

  The size of the negative refractive index medium 301 can be reduced by reducing the value of t0.

  It is desirable that the value of t0 be variable by devising the mechanical structure of the optical device. One example is a microscope stage.

  Further, the negative refractive index medium 301 may be formed and disposed on a transparent flat plate. If the lens or flat plate used as the substrate is made of a material having a positive refractive index, it can be manufactured at low cost.

  Further, when the refractive index of the negative refractive index medium 301 is ns, ns <0. When the negative refractive index medium 301 is a parallel plate, ideally ns / n0 = -1. However, in practice, there may be a case where ns / n0 = −1 cannot be achieved due to a manufacturing error of the negative refractive index medium 301, a shift of the used wavelength, or the like. At this time, it is desirable to satisfy the following equation.

−1.1 <ns / n0 <−0.9 (9)
If the value of ns / n0 deviates from the above, the resolution decreases. Depending on the product: −1.5 <ns / n0 <−0.5 Formula (10)
If it is good.

Depending on the application, −3 <ns / n0 <−0.2 (11)
But sometimes it ’s okay.

  Note that the negative refractive index medium 301 may be surrounded by air, vacuum, water, oil, or the like as is common to the embodiments of the present application.

  Further, in the examples of FIGS. 1, 3, 4, 5, 6, and 7, the portion t0 may be filled with a liquid such as water or oil. In this way, the value of ns does not have to be −1, and there is an advantage that the material of the negative refractive index medium 301 can be easily selected.

  When the periphery of the negative refractive index medium 301 is evacuated, it is possible to use vacuum ultraviolet light having a short wavelength, and there is no reduction in resolution due to air fluctuations, and so on, thereby providing good imaging performance. If the surroundings are air, an optical device can be easily manufactured and handled easily. Of the optical device, only the optical path around the negative refractive index medium 301 may be evacuated, and the rest of the optical device may be placed in the air.

  An optical device that is easy to handle and has good imaging performance can be obtained.

  Let nA be the refractive index of air against vacuum. NA = 1.0002818 when the pressure is 1 atm and the wavelength is 500 nm.

The value of t will be described. In practice, it is better to increase the working distance in order to improve the usability of the optical device. From the equation (19), the working distance is a value similar to t. Therefore, 0.1 mm <= t <= 300 mm ... Formula (15-2)
It is good to do. If the value of t exceeds the upper limit, the optical device becomes large and difficult to manufacture.

0.01mm ≦ t ≦ 300mm depending on the product (16-2)
But it is acceptable.

Depending on the application, 1100 nm ≦ t ≦ 200 mm (17)
Alternatively, in the case where the negative refractive index medium 301 has light absorption, 30 nm ≦ t ≦ 50 mm (18)
But sometimes it is acceptable.

  Further, if the expression 15-2 or 16-2 is satisfied, the mechanical strength of the negative refractive index medium as an optical element increases, so that the handling at the time of assembling the optical device may be facilitated.

  Alternatively, there is a possibility that a substrate for supporting the negative refractive index medium may be unnecessary.

  If the upper limit of t is set to 0.01 mm in the equations (17) and (18), the negative refractive index medium may be manufactured as a thin film by vapor deposition or sputtering.

  For example, it is conceivable to produce a photonic crystal by a self-cloning method (see Non-Patent Document 4).

  In addition, if the length measured along the optical axis of the optical system including the negative refractive index medium is 20 m or less, the optical system and the optical device can be easily manufactured.

  Finally, definitions of technical terms used in this embodiment will be described.

  An optical device is a device including an optical system or an optical element. The optical device alone may not function. That is, it may be a part of the apparatus.

  The optical device includes an imaging device, an observation device, a display device, an illumination device, a signal processing device, an optical information processing device, a projection device, a projection exposure device, and the like.

  Examples of imaging devices include film cameras, digital cameras, PDA digital cameras, robot eyes, interchangeable lens digital single lens reflex cameras, television cameras, video recording devices, electronic video recording devices, camcorders, VTR cameras, and mobile phones. Digital camera, mobile phone TV camera, electronic endoscope, capsule endoscope, in-vehicle camera, satellite camera, planetary explorer camera, space probe camera, surveillance camera, various sensor eyes, recording There are digital cameras, artificial vision, laser scanning microscopes, projection exposure apparatuses, steppers, aligners, optical probe microscopes, near-field microscopes, and the like. Digital camera, card-type digital camera, TV camera, VTR camera, video recording camera, mobile phone digital camera, mobile phone TV camera, in-vehicle camera, satellite camera, planetary probe camera, space probe camera, recording device These digital cameras are examples of electronic imaging devices.

  Examples of the observation apparatus include a microscope, a telescope, glasses, binoculars, a loupe, a fiberscope, a viewfinder, a viewfinder, a contact lens, an intraocular lens, and artificial vision.

  Examples of the display device include a liquid crystal display, a viewfinder, a game machine (Sony PlayStation), a video projector, a liquid crystal projector, a head mounted display (HMD), a PDA (personal digital assistant), Mobile phones, artificial vision, etc.

  Video projectors, liquid crystal projectors, etc. are also projection devices.

  Examples of the illumination device include a camera strobe, an automobile headlight, an endoscope light source, and a microscope light source.

  Examples of signal processing devices include mobile phones, personal computers, game machines, optical disk reading / writing devices, computing devices for optical computers, optical interconnection devices, optical information processing devices, optical LSIs, optical computers, PDAs, etc. .

  An information transmission device is a device that can input and transmit any information such as a remote control such as a mobile phone, a fixed phone, a game machine, a TV, a radio cassette, a stereo, a personal computer, a keyboard of a personal computer, a mouse, a touch panel, etc. Point to.

  It shall also include a television monitor with an imaging device, a personal computer monitor, and a display.

  The information transmission device is included in the signal processing device.

  The imaging device refers to, for example, a CCD, an imaging tube, a solid-state imaging device, a photographic film, and the like. The plane parallel plate is included in one of the prisms. The change of the observer includes the change of the diopter. The change in the subject includes a change in the object distance as the subject, movement of the object, movement of the object, vibration, blurring of the object, and the like. Imaging elements, wafers, optical disks, silver salt films, etc. are examples of imaging members.

  The definition of the extended surface is as follows.

  In addition to spherical surfaces, flat surfaces, and rotationally symmetric aspheric surfaces, spherical surfaces that are decentered with respect to the optical axis, flat surfaces, rotationally symmetric aspheric surfaces, aspheric surfaces that have a symmetric surface, aspheric surfaces that have only one symmetric surface, and non-symmetrical surfaces Any shape such as a spherical surface, a free-form surface, a non-differentiable point, or a surface having a line may be used. It may be a reflective surface or a refractive surface as long as it can have some influence on light.

  In the present invention, these are collectively referred to as an extended curved surface.

  The imaging optical system refers to an imaging optical system, an observation optical system, a projection optical system, a projection exposure optical system, a display optical system, a signal processing optical system, and the like.

  An example of the imaging optical system is an imaging lens for a digital camera.

  Examples of the observation optical system include a microscope optical system and a telescope optical system.

  Examples of the projection optical system include a video projector optical system, a lithography optical system, an optical disk read / write optical system, and an optical pickup optical system.

  As an example of the projection exposure optical system, there is an optical system for lithography.

  An example of the display optical system is a viewfinder optical system of a video camera.

  Examples of the signal processing optical system include an optical disk read / write optical system and an optical pickup optical system.

  An optical element refers to a lens, an aspheric lens, a mirror, a mirror, a prism, a free-form surface prism, a diffractive optical element (DOE), a heterogeneous lens, and the like. A parallel plate is also an optical element.

The present invention also has various features as described below.
(Appendix)
20. A light source, an optical element formed of a medium exhibiting negative refraction, an aperture member or a probe for light detection or illumination, and the intensity of the evanescent wave emitted from the object is the intensity of the evanescent wave in the object An optical device, wherein the opening member or the probe is disposed in a larger area.

20-1. An evanescent light emitted from the object, comprising: a light source; a probe for light detection or illumination; and an optical element formed of a medium exhibiting negative refraction disposed between the object and the aperture member or the probe. An optical apparatus, wherein the opening member or the probe is arranged in a region where the intensity of the wave is larger than the intensity of the evanescent wave in the object.

20-2. A light source, a probe for light detection or illumination, and an optical element formed of a medium exhibiting negative refraction disposed between the object and the aperture member or the probe, and the equations (19, 20) Or an optical device satisfying the expression 20-2.

30. A light source, an optical element formed of a medium exhibiting negative refraction, and an opening member or probe for light detection or illumination; and when converting light detected by the opening member or probe into an electrical signal An optical device characterized by considering the amplification factor of evanescent waves by an optical element formed of a medium exhibiting negative refraction.

30-1. A light source; an optical element formed of a medium exhibiting negative refraction; an aperture member or probe for light detection or illumination; and a conversion element that converts light detected by the aperture member or probe into an electrical signal. And an evanescent wave amplification factor by an optical element formed of a medium exhibiting negative refraction when the electric signal is converted into an image signal.

30-2. A light source; an optical element formed of a medium exhibiting negative refraction; an aperture member or probe for light detection or illumination; and a conversion element that converts light detected by the aperture member or probe into an electrical signal. And an evanescent wave amplification factor by an optical element formed of a medium exhibiting negative refraction when the electric signal is converted into an image signal.

30-3. A light source; an optical element formed of a medium exhibiting negative refraction; an aperture member or probe for light detection or illumination; and a conversion element that converts light detected by the aperture member or probe into an electrical signal. When the electric signal is converted into an image signal, Equation 24. An optical device according to claim 1.

40. A light source, an optical element formed of a medium exhibiting negative refraction, and a minute object for light scattering, and in an area where the intensity of the evanescent wave emitted from the object is larger than the intensity of the evanescent wave in the object An optical apparatus, wherein the light scattering minute object is arranged.

40-1. An optical element that is disposed between a light source, a minute object for light scattering, an object, and a medium that exhibits negative refraction, and optics that collects light scattered by the minute object And a conversion element that converts the light collected by the optical system into an electric signal, and the light is emitted in a region where the intensity of the evanescent wave emitted from the object is larger than the intensity of the evanescent wave in the object. An optical apparatus in which a minute object for scattering is arranged.

40-1-1. When converting the electrical signal into an image signal, an amplification factor of an evanescent wave by an optical element formed of a medium exhibiting negative refraction is considered 40-1. Optical device.

50. 21. scanning the opening member, the probe, or the minute object with respect to the object; ~ 40-1-1. An optical device according to any one of the above.

51. 21. Scanning the object with the aperture member, the probe, or the minute object together with an optical element formed of the medium exhibiting negative refraction. ~ 40-1-1. An optical device according to any one of the above.

52. 20. Expression 25 is satisfied To 51. An optical device according to any one of the above.

53. 20. Expression 26 or Expression 18-1 is satisfied To 51. An optical device according to any one of the above.

60. 21. The optical element formed of a medium exhibiting negative refraction is a parallel plate. The optical device according to any one of ˜51.

60-1. 20. The thickness of the optical element formed of the medium exhibiting negative refraction satisfies either of the expressions (17) and (18) The optical device according to any one of 1 to 60.

61. The optical element formed of a medium exhibiting negative refraction having an optical element formed of a material having a positive refractive index is formed on the substrate using the optical element formed of a material having a positive refractive index as a substrate. 20. It is formed. ~ 60. An optical device according to any one of the above.

65. 20. The refractive index of the medium exhibiting negative refraction satisfies the formula (11). ~ 61. An optical device according to any one of the above.

66. 20. Light passes through the medium exhibiting negative refraction a plurality of times. -65. An optical device according to any one of the above.

67. 20. A light receiving element is provided. 66. The optical device according to any one of -66.

68. The distance between the negative refraction medium and the object is variable. -67 The optical apparatus as described in any one of -67.

69. 20. The light used is monochromatic light. 70. The optical device according to any one of ˜68.

70. The wavelength of light used is 0.1 μm or more and 3 μm or less. The optical device according to any one of? 69.

71. 20. The medium exhibiting negative refraction is a photonic crystal. -70. An optical device according to any one of the above.

71-1. 71. A photonic crystal is used as the medium exhibiting negative refraction, and the axis having the best rotational symmetry of the photonic crystal faces the optical axis direction of the objective optical system. An optical device according to 1.

71-2. 72. The optical apparatus according to 71, wherein any one of formulas (5-4), (5-5), and (5-6) is satisfied.

72. The medium exhibiting negative refraction is a negative refractive index medium. An optical device according to any one of the above.

72-2. 20. The medium exhibiting negative refraction is a medium exhibiting complete imaging properties. To 70. An optical device according to any one of the above.

72-3. 20. The medium exhibiting negative refraction is a thin film of a material having a negative dielectric constant. To 70. An optical device according to any one of the above.

72-4. 20. The medium exhibiting negative refraction is a thin film of a material having a negative dielectric constant, and satisfies the formula 5-8. To 70. An optical device according to any one of the above.

73. The optical apparatus according to any one of 20 to 72-4, wherein the optical apparatus is a near-field microscope.

75. 73. The near-field microscope is a reflection type. Optical device.

76. 73. The near-field microscope is a transmission type. Optical device.

77. 74. The optical device according to any one of 20 to 73, comprising an optical system having an optical element formed of a medium exhibiting negative refraction and an optical element having a positive refractive index.

78. 74. The optical device according to any one of 20 to 73, wherein the light source is a laser.

79. The air around the medium exhibiting negative refraction is air. 74. The optical device according to any one of items 1 to 73.

80. 21. The optical element formed of the medium exhibiting negative refraction has a curved optical surface. 74. The optical device according to any one of items 73 to 73.

It is a figure which shows the structure of the near field microscope 401 using the negative refractive index medium 301 based on one Embodiment of this invention. It is a figure which shows the relationship between an object surface, a negative refractive index medium, and a detection surface. It is a figure which shows the structure of the near field microscope 401 using the negative refractive index medium 301 based on other embodiment of this invention. FIG. 10 is a view showing a transmission near-field microscope 315 using a negative refractive index medium 301, which is still another embodiment of the present invention. It is another embodiment of the present invention, and is a view showing an atomic force microscope type near-field microscope 912 using a cantilever 911 as a minute object for light scattering. It is a figure which shows the near field microscope 318 which used together the board 916 which has the pinhole 915, and the negative refractive index medium 301. FIG. It is a figure which shows embodiment using the negative refractive index medium lens 301-3 which has a convex surface on the object side. It is a figure which shows the 1st specific example of the photonic crystal 340 as a specific substance of the negative refractive index medium 301. FIG. It is a figure which shows the 2nd specific example of the photonic crystal 340. FIG. It is a figure for demonstrating the specific structure using the negative refractive index medium 301. FIG. It is a figure which shows a mode that the intensity | strength of an evanescent wave changes. It is a figure which shows the structure of the conventional near field microscope 901. FIG.

Explanation of symbols

301 Negative refractive index medium 303 Light source 307 Object 310 Upper surface 312 Object side surface 314 Object 315 Near field microscope 317 Prism 318 Surface 401 Near field microscope 401-2 Near field microscope 890 Illumination lens 891 Slide glass 894 Signal processing device 895 Computer 896 Television monitor 898 Detection surface 902 Half prism 903 Lens 904 Optical fiber probe 905 Glass fiber 906 Metal coating 907 Opening 908 Photomultiplier 911 Cantilever 912 Atomic force microscope Near field microscope

Claims (3)

A light source;
An optical element formed of a medium exhibiting negative refraction;
An opening member or probe for light detection or illumination,
An optical device, wherein the aperture member or the probe is arranged in a region where the intensity of an evanescent wave emitted from an object is larger than the intensity of the evanescent wave in the object. A light source;
An optical element formed of a medium exhibiting negative refraction;
An opening member or probe for light detection or illumination,
An optical device characterized by considering an evanescent wave amplification factor by an optical element formed of a medium exhibiting negative refraction when converting light detected by the aperture member or the probe into an electric signal. A light source;
An optical element formed of a medium exhibiting negative refraction;
A small object for light scattering,
An optical apparatus, wherein the light scattering minute object is arranged in a region where the intensity of the evanescent wave emitted from the object is larger than the intensity of the evanescent wave in the object.

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