JP2004031869A - Near-field optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a near-field optical element provided with a light emitting part formed on the surface of a transparent substrate and a light shielding film having the fine opening part of the half wavelength or less of a wavelength emitted by the light emitting part on the back surface, which emits near-field light from the fine opening part. <P>SOLUTION: The near-field optical element 100 is composed of a transparent sapphire substrate 1, the laminated structure 2 of a group 3 nitride compound semiconductor having the light emitting part formed on the surface, the light shielding film 3 formed on the back surface of the sapphire substrate 1 and the fine opening part 4 of the light shielding film 3. A spindle-shaped projection part 10 is formed on the back surface of the sapphire substrate 1 and the fine opening part 4 is formed by removing the light shielding film 3 only at the tip part 11. The size d of the tip part 11 of the projection part 10 where the light shielding film 3 is removed is turned to be about 1/2 or less of an emitted light wavelength. Such a near-field optical element 100 can emit the near-field light at the fine opening part 4 having a diameter d of about 1/2 or less of the emitted light wavelength of the laminated structure 2 of the group 3 nitride compound semiconductor. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is an invention of a near-field light element that emits near-field light, that is, a surface electric field generated only on the surface of an object.
[0002]
[Prior art]
There has recently been a growing interest in measuring devices that use near-field light with sub-wavelength resolution (eg, Applied Physics Vol. 71 (2002), pp. 653-663 and 700-704). At this time, in order to generate near-field light, laser light is converted into pattern light through a pattern generator, and then only the distal end portion is output as a fine aperture to an optical fiber whose other surface is coated with a metal. One that emits near-field light is known (FIG. 1 on page 701 of the same).
[0003]
[Problems to be solved by the invention]
The combination of a laser light generating device and an optical fiber whose other surface is covered with metal only with a fine opening at the tip is a large-scale device, and the manufacturing of the optical fiber is not always simple.
[0004]
An object of the present invention is to provide an extremely small near-field light utilization device by providing a completely new near-field light element.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, according to the means of claim 1, the transparent substrate, the light emitting portion formed on the transparent substrate surface, and the transparent substrate back surface, the half wavelength or less of the wavelength emitted by the light emitting portion. A near-field light element having a light blocking film having at least one minute opening and emitting near-field light from the minute opening.
[0006]
According to a second aspect of the present invention, the transparent substrate is sapphire, and the light emitting portion is a group III nitride compound semiconductor light emitting device formed on the sapphire substrate.
[0007]
[Action and effect of the invention]
If a light-emitting portion is provided on the front surface side of the transparent substrate and a light-blocking film having at least one minute opening of a half wavelength or less of the wavelength emitted by the light-emitting portion is formed on the back surface, near-field light can be emitted from the minute opening. It is possible. The near-field optical element having such a novel configuration replaces the combination of the conventional laser light generating device and the optical fiber whose other surface is metal-coated as a minute opening only at the tip, and is combined with other equipment. It is possible to reduce the configuration of a desired measuring device as a whole (claim 1).
[0008]
If a combination of a sapphire substrate and a group III nitride compound semiconductor light emitting device formed thereon is used, the sapphire substrate is insulative, and the electrodes and the like required for the group III nitride compound semiconductor light emitting device are on the front side. And the back surface can be processed freely (claim 2).
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The present invention is not limited by the attached drawings and the following description.
[0010]
[First embodiment]
FIG. 1 is a cross-sectional view illustrating a configuration of a near-field light element 100 according to a first specific example of the present invention. The near-field light element 100 includes a transparent sapphire substrate 1, a laminated structure 2 of a group III nitride compound semiconductor having a light emitting portion formed on the surface thereof, a light blocking film 3 formed on the back surface of the sapphire substrate 1, It consists of minute openings 4 in the blocking film 3. The near-field light element 100 shown in FIG. 1 has a configuration in which a weight-shaped protruding portion 10 is formed on the back surface of the sapphire substrate 1, and the minute opening 4 is formed only in the tip portion 11 except for the light blocking film 3. The size (diameter) d of the tip portion 11 of the protruding portion 10 excluding the light blocking film 3 is preferably set to be about ２ or less of the emission wavelength. In addition, for forming the protruding portion 10 in the shape of a cone on the back surface of the sapphire substrate 1, etching, a combination of mechanical polishing or the like and etching can be used. Further, as the light shielding film 3, a metal vapor-deposited film, a cured opaque resin, or any other material can be used. As a method of forming the small opening 4 only at the tip portion 11 of the projecting portion 10, the entire back surface of the sapphire substrate 1 having the projecting portion 10 is once covered with the light blocking film 3, and only the tip portion 11 is covered with a photolithographic mask. It may be removed by using. The near-field light element 100 in FIG. 1 can emit near-field light in the minute opening 4 having a diameter d of about の or less of the emission wavelength. Therefore, the near-field light element 100 of FIG. 1 replaces a conventional laser device and a near-field light generation device that is a combination of an optical fiber with a processed tip, and a measuring device or the like combined with a desired probe or the like. The overall device configuration can be reduced.
[0011]
If the light emitting element is a laser diode, coherent light can be used, so that it is possible to further improve the resolution of a desired measuring device combined with another instrument. Preferably, the laser light oscillates in the vertical direction in FIG.
[0012]
[Second embodiment]
FIG. 2 is a cross-sectional view illustrating a configuration of a near-field light element 200 according to a second specific example of the present invention. The near-field light element 200 has a structure in which many small openings 4 of the near-field light element 100 of FIG. 1 are provided. The near-field light element 200 shown in FIG. 2 is a near-field light element that can emit a large number of near-field lights to a region close to one element, and can perform various measurements by combining with a desired probe or the like. It can be.
[0013]
[Third embodiment]
FIG. 3 is a sectional view showing a configuration of a near-field light element 300 according to a third specific example of the present invention. The near-field light element 300 is a case where the laminated structure 2 of the group III nitride compound semiconductor having the light-emitting part of the near-field light element 100 of FIG. In addition, the resonance mirrors 21 and 23 are clearly shown. The portion sandwiched between the laser resonance mirrors is a laser diode light emitting section 22 having a laminated structure of a group III nitride compound semiconductor. The near-field light element 300 in FIG. 3 is a near-field light element capable of emitting a large number of near-field lights to a region in close proximity with one element, similarly to the near-field light element 200 in FIG. Various measurements can be made possible by combining with the above-mentioned probe and the like. The laser light is a surface emitting laser diode that oscillates in the vertical direction in FIG.
[0014]
1 to 3, only the essence of the present invention is shown, so that the electrodes and other components are omitted. For example, after the electrodes are formed, all the surfaces except the electrodes and the minute openings 4 are coated with light. It may be covered with a blocking film 3. If a light-reflecting film is used as the light-shielding film, or if the electrode is made of a metal with high reflectivity as the uppermost layer, light leakage can be suppressed, and heat radiation can be performed with a very small amount of power. It is possible to drive the near-field light element with less.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a configuration of a near-field light element according to a first specific example of the present invention.
FIG. 2 is a sectional view showing a configuration of a near-field light element according to a second specific example of the present invention.
FIG. 3 is a sectional view showing a configuration of a near-field light element according to a third specific example of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 Sapphire substrate 2 Group III nitride compound semiconductor laminated structure having light emitting part 20 Laser diode part 22 composed of group III nitride compound semiconductor laminated structure 22 Laser diode light emission composed of group III nitride compound semiconductor laminated structure Units 21 and 23 Laser resonance mirror 3 Light blocking film 10 Conical projection 11 Protrusion tip 4 Micro aperture 100, 200, 300 Near-field optical element

Claims (2)

A transparent substrate,
A light emitting unit formed on the surface of the transparent substrate,
On the back surface of the transparent substrate, having a light blocking film having at least one minute opening of a half wavelength or less of the wavelength emitted by the light emitting unit,
A near-field light element that emits near-field light from the minute opening. The transparent substrate is sapphire,
The near-field light device according to claim 1, wherein the light-emitting portion is a group III nitride compound semiconductor light-emitting device formed on a sapphire substrate.

Images