JP3842011B2 - Light emitting medium for optical recording and optical recording apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
Due to the explosive increase in the amount of information delivered by high-speed and wide-area communication networks such as the Internet in recent years and the dramatic increase in the size of computer software and the amount of processing data, the capacity of optical recording devices that record these information has increased. There is a strong demand. In addition, various electronic devices have been miniaturized, and the need for a small and light mass storage device that can be mounted on a satellite or a mobile (mobile, wearable) communication device is increasing. These were the background, recording capacity required is several orders of magnitude increase in the short term, 1 m ² per 1550 terabits [per square inch 1 tera (10 ^{12: T)} bits] referred to above (hereinafter Terabit ) Is very eager to realize, and the range of use and market size are very large (Reference: Optoelectronic Industry Technology Promotion Association, “Optical Industry Roadmap”).
The present invention relates to a light-emitting medium for optical recording having an ultrahigh recording surface density of the terabit class and an optical recording apparatus using the same.
[0002]
[Prior art]
Conventionally, a recording apparatus has mainly used a magnetic recording system in which a difference in magnetization direction of a magnetic recording material is used as a recording unit. For this purpose, a hard disk in which a recording medium and a signal detection mechanism are integrated, and a floppy disk that can be carried separately from the signal detection mechanism are widely used. In recent years, an optical recording system in which a recording material is focused and irradiated with laser light with a lens and a difference in optical characteristics of the recording material generated at that time is recorded / reproduced as a recording unit has been remarkably developed. As examples of the optical recording system, a compact disk (CD), a digital video disk (DVD), a magneto-optical disk (MO disk), and the like are widely used.
[0003]
[Problems to be solved by the invention]
In the terabit-class recording surface density, the size of the recording unit (pit) must be extremely small (nm = 10 ⁻⁹ ) or less (nm = 10 ⁻⁹ ) (hereinafter referred to as such nanometer-sized pits). Will be called nanopits). Conventionally used magnetic recording methods include a longitudinal magnetic recording method and a perpendicular magnetic recording method.
[0004]
Currently, the longitudinal magnetic recording system in practical use has a physical limit that makes it impossible to maintain the reversal of magnetic domains when the pit size reaches the nm level. As a result, the recording surface density of the magnetic recording system is limited to about 20 giga (10 ⁹ : G) bits, and it is difficult to realize a terabit class recording apparatus by the magnetic recording system. Further perpendicular magnetization scheme high areal density is expected, prospect of practical application of what many years research has been carried out is not standing. Also, in the conventional optical recording method using laser light focused by a lens, the light irradiation range cannot be reduced to less than half the wavelength of light (submicron level) due to the light diffraction limit, so the surface recording density is limited to about 10 Gbits. However, it cannot be applied to a terabit class recording apparatus that also requires nanopits.
[0005]
In recent years, an attempt has been made to realize a high-density optical recording apparatus by using light (referred to as near-field light) that oozes out from a probe having an aperture smaller than the wavelength of light and localizes in a region smaller than the wavelength of light. Research has been done. However, when trying to excite nanopits with the near-field light itself, the proportion of light lost as heat in the probe becomes very large, and the aperture size of the light that can be practically recorded and reproduced is about the nanopit size. There is a problem that the probe breaks due to heat generation when trying to irradiate from the minute aperture. Therefore, in order to efficiently inject the excitation power for light emission into the nanopits, a method using a current discharged from the tip of a sharpened conductive material (conductive probe) has been proposed. In this way, current can be injected into the nanometer-sized region in the medium with little loss. However, in the conventional technology, the material and structure of the light emitting medium are not necessarily optimal for obtaining sufficient light emission intensity as an optical memory, and in order to realize an optical recording device with a terabit class ultra-high recording surface density, higher efficiency is required. Realizing a luminescent medium has been a challenge.
[0006]
The object of the present invention is to use a current that can efficiently inject power into a nanometer-sized minute region, rather than light having a submicron level diffraction limit as an optical excitation means, in order to solve the above-described problems in the prior art. Furthermore, by using a configuration that efficiently collects light generated from a minute region by this current, an optical recording light-emitting medium having a terabit-class ultrahigh recording surface density and an optical recording apparatus using the same are provided. There is.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems of the present invention, the present invention is configured as described in the claims. That is,
The present invention provides a light-emitting medium for optical recording that generates light by external excitation as described in claim 1, and the light-emitting medium for optical recording includes a pair of barrier layers for electrons and these barrier layers. The barrier layer placed at the lower side of the electron confinement layer among the barrier layers of the light emitting medium has a structure in which the barrier effect on holes is smaller than the barrier effect on electrons compared to the barrier effect on electrons. This is a light emitting medium for optical recording.
[0009]
In addition, as described in claim 2 , in the light-emitting medium for optical recording according to claim 1, the electron confinement layer of the light-emitting medium is made of AlGaAs having an Al composition ratio of 0.4 or less, and is formed under the confinement layer. A barrier layer placed on the side is made of AlAs, and a light-emitting medium for optical recording having a structure in which the Al concentration continuously changes between the confining layer made of AlGaAs and the AlAs barrier layer below the confining layer; To do.
[0010]
Further, as described in claim 3 , in the light-emitting medium for optical recording according to claim 1, the barrier layer disposed on the surface side of the electron confinement layer among the barrier layers of the light-emitting medium is made of an InGaP compound. The light-emitting medium for optical recording has a thickness of the barrier layer in the range of 5 nm to 20 nm.
[0011]
Further, as described in claim 4 , in the light-emitting medium for optical recording according to claim 1, the barrier layer installed on the surface side of the electron confinement layer among the barrier layers of the light-emitting medium is made of an InGaP compound. The light-emitting medium for optical recording has a thickness of the barrier layer in the range of 8 nm to 15 nm.
[0012]
Further, as described in claim 5 , in the light-emitting medium for optical recording according to claim 1, the electron confinement layer of the light-emitting medium is smaller than the band gap of the portion of the electron confinement layer, and The light-emitting medium for optical recording has a structure including a portion of the electron confinement layer whose layer thickness is smaller than the electron wavelength.
[0013]
In addition, as described in claim 6 , in the optical recording light-emitting medium according to any one of claims 1 to 5 , the optical recording light-emitting medium is larger than a recording unit size in a plane. It is subdivided into nanometer-sized microcompartments that restrict the movement of current to each other, and the microcompartments are composed of a signal light generating region that generates light by current and a signal light non-generating region that does not generate signal light, and the light emission The medium is a light-emitting medium for optical recording having a structure having at least a protective layer on the surface and held by a substrate.
[0014]
Further, as described in claim 7 , in the light-emitting medium for optical recording according to any one of claims 1 to 6 , a material that reflects light is provided on the substrate, or light is irradiated. The light-emitting medium for optical recording is formed in a reflecting shape.
[0015]
In addition, as described in claim 8 , in the light-emitting medium for optical recording according to any one of claims 1 to 7 , an electrode layer is provided on the substrate, or a conductive substrate. Is used as a light-emitting medium for optical recording.
[0016]
In addition, as described in claim 9 , the optical recording light-emitting medium according to any one of claims 1 to 8 and a nanometer-sized region in the light-emitting medium are excited to generate light. An optical recording apparatus comprising at least a conductive condensing probe having conductivity and light transmission, wherein the light emitting medium and the conductive condensing probe are held at a distance in a range in which a current flows between them, or The optical recording apparatus has a structure in which both are held in contact with each other, a current is passed between the tip of the conductive condensing probe and the light emitting medium, and light emitted thereby is collected by the conductive condensing probe. is there.
[0017]
Further, as described in claim 10 , in claim 9 , the distance between the conductive condensing probe and the light emitting medium is maintained at a distance that allows the current to reach by a tunnel effect, and causes the light emitting medium to emit light. The optical recording device has a structure that uses a current that flows due to the tunnel effect.
[0018]
Further, as described in claim 11 , in the structure according to claim 9 , the current that flows through the contact is used as the current that causes the conductive condensing probe and the light-emitting medium to contact each other and causes the light-emitting medium to emit light. This is an optical recording apparatus.
[0019]
Here, the lower side means the lower side of the electron confinement layer with respect to the current injection direction, and the surface side means the upper side of the electron confinement layer with respect to the direction of current injection.
[0020]
In the present invention, current or light is supplied from a probe having a sharp tip to a minute region of a light-emitting medium for optical recording, and light emission generated thereby is condensed by the probe or other means, and the collected light is signaled. By using an optical recording light emitting medium that increases the light emission and detection efficiency by concentrating the current or light injected from the probe in a very small area, a terabit-class ultrahigh recording surface density can be obtained. An optical recording apparatus is provided.
[0021]
That is, in an optical recording apparatus having a light-emitting medium for optical recording that generates light by excitation from the outside, means for generating light by exciting a nanometer-sized region in the light-emitting medium, and means for detecting the light emission The light emitting medium uses a light emitting medium for optical recording composed of a pair of barrier layers against electrons and an electron confinement layer sandwiched between these barrier layers.
[0022]
The present invention employs a light-emitting medium for optical recording having the material and structure as described in the above claims, and can generate read light with sufficient intensity from nanometer-sized pits. There is an effect of realizing an optical recording apparatus having a high recording surface density of a class.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of the embodiment of the present invention includes a basic embodiment 1 for an optical recording light-emitting medium and its application examples (embodiments 2 to 4). There are two types of optical recording apparatuses, such as a hard disk, in which a recording medium and a probe are integrated, and a recording medium such as a floppy disk or a magneto-optical (MO) disk that is portable. Is applicable to any configuration.
[0024]
<Embodiment 1>
First, Embodiment 1 of the present invention will be described with reference to FIG. 1 and FIG. In FIG. 1, 1 is a conductive condensing probe, 2 is an optical fiber, 3 is a transparent conductive film, 4 is a light emitting medium for optical recording, 5 is a surface protective layer (or upper barrier layer), 6 is a light emitting material for optical recording, Reference numeral 6a denotes a signal light generation region that generates signal light and is referred to as a pit. Reference numeral 6b denotes a signal light non-generation region that does not generate signal light. The signal light generation region 6b is an area having partitioning between adjacent pits and signal information inverted from 6a. 7 is an electrode layer, 8 is a light reflection layer, 9 is a substrate, 10 is a photodetector, 11 is a signal processing circuit, 12 is an injection current, 13 is detection light, 14 is near-field light, 15 is a bias power source, and 20 is The gap between the probe and the media surface is shown. In FIG. 2, 16 is a hole. Reference numeral 17 denotes an upper barrier layer, which may also serve as a surface protective layer. 18 is a well layer, 19 is a bottom barrier layer, and 20 is a gap between the probe and the medium surface.
[0025]
The conductive condensing probe 1 has, for example, a structure in which a transparent conductive film 3 is coated on the surface of an optical fiber 2 whose tip is sharpened to a nanometer size. Examples of the material of the transparent conductive film 3 include indium oxide and zinc oxide excellent in conductivity and transparency, or ultrathin films of diamond-like carbon and metal. The tip of the probe has conductivity and transparency, and injects a tunnel current into the light emitting medium 4 and simultaneously collects light from the light emitting medium 4. The current injection may be performed with a conductive probe, and the condensing may be performed with a condensing optical element (for example, a lens or a reflecting mirror) provided separately.
[0026]
The light recording medium 4 for optical recording forms a film structure on the surface of the substrate 9 in the order of a bottom barrier layer 19, a well layer 18, and an upper barrier layer 17. Further, if necessary, the light reflecting layer 8 or the electrode layer 7 (when the substrate is insulative), the light-emitting material 6 for optical recording, and the upper barrier layer 17 (or the surface) are provided between the substrate 9 and the bottom barrier layer 19. The protective layer 5) is formed in order. When the substrate 9 and the light reflection layer 8 have sufficient conductivity, the electrode layer 7 is not necessary because they function as an electrode layer.
[0027]
In this embodiment, the bottom barrier layer 19 is made of AlAs, the well layer (confinement layer) 18 is made of Al _x Ga _1-x As which is a direct transition material (x <0.4), and the upper barrier layer 17 is made of InGaP. The case where a compound is used will be described. In the confinement layer (well layer 18), only GaAs not containing Al may be used.
[0028]
The light-emitting material 6 for optical recording is a material that emits light by current injection. For example, AlGaAs, GaN, InP, ZnO, etc., which are direct transition semiconductors, Si fine particles having a fine grain boundary, fullerene, or Alq (aluminum). There are organic polymers such as quinoline.
[0029]
FIG. 3 shows an energy band of the structure of the light emitting medium shown in FIG. In FIG. 3, 1 is a conductive condensing probe, 20 is a gap between the probe and the medium surface, 4 is a light emitting medium for optical recording, 7 is an electrode layer, 9 is a substrate, 17 is an upper barrier layer, and 18 is a well layer (electron). The confinement layer) 19 is a bottom barrier layer, and the injection current 12 becomes detection light 13 and flows to the conductive condensing probe 1 in the direction of the arrow, and the hole 16 flows in the direction of the arrow, and the well Recombination emission occurs by recombination with the electrons of the layer 18. The electrons confined in the well layer 18 do not dissipate to the substrate 9 or the medium surface but concentrate in the spatially narrow well layer 18, so that strong light emission occurs.
The tip of the probe is brought close to the distance through which the tunnel current near the surface of the optical recording light emitting medium flows. The distance through which the tunnel current flows depends on the bias voltage applied between the probe and the medium, but is usually on the nanometer level. Further, the probe may be brought into contact with the light emitting medium. In this case, a current larger than the tunnel current can be injected into the medium. However, in order to prevent the probe and the medium from being worn, a means for holding the contact pressure of the probe to the medium constant, the probe and the medium Add a means to reduce the friction with. The position of the probe on the recording medium is relatively moved while maintaining the contact distance or the distance through which the tunnel current flows. A bias voltage is applied between the probe and the medium surface so that the current radiated from the probe has energy exceeding the upper barrier layer of the medium. The current from the probe passes through the potential of the upper barrier layer and reaches the well layer. The injected electrons lose energy in the well layer and relax to the bottom of the energy band. Electrons whose energy has been relaxed in the well layer cannot cross the bottom barrier layer and do not diffuse into the substrate. On the other hand, electrons heading toward the medium surface in the well layer are similarly reflected by the upper barrier layer and do not diffuse to the surface. In this way, electrons once injected into the well layer, or electrons newly generated in the confinement layer by the electrons are confined in the well layer. In the well layer, since the material is set so that light is emitted when electrons and holes are recombined, the confined electrons quickly recombine and emit light. Since electrons do not dissipate to the substrate or the medium surface but concentrate in a spatially narrow well layer, a strong light emission intensity can be obtained.
[0030]
<Embodiment 2>
In this embodiment mode, a light-emitting medium for optical recording having a structure shown in FIG. 4 and a light-emitting medium having an energy band structure shown in FIG. 5 will be described. In FIG. 4, 1 is a conductive condensing probe, 20 is a gap between the probe and the medium surface, 4 is a light-emitting medium for optical recording, 7 is an electrode layer, 9 is a substrate, 12 is an injected current, 13 is detection light, 16 is Holes, 17 are upper barrier layers, 18 are well layers (electron confinement layers), 19 are bottom barrier layers, and 19-1 is a potential gradient region of the bottom barrier layers. In FIG. 5, the injection current 12 passes through the well layer 18 and becomes the detection light 13 and flows in the direction of the conductive condensing probe 1. The holes 16 flow in the direction of the well layer 18, and recombine light emission by recombination with electrons confined in the well layer 18. The electrons confined in the well layer 18 do not dissipate to the substrate 9 or the medium surface but concentrate in the spatially narrow well layer 18, so that strong light emission occurs.
[0031]
In the present embodiment, the case where a structure in which the band structure of the conduction band is convex upward and the band structure of the valence band is flat will be described as the bottom barrier layer 19. This band structure is obtained by forming the potential gradient region 19-1 of the bottom barrier layer, which is a region where the potential continuously changes, on both the upper and lower sides of the bottom barrier layer 19. Due to this band structure, the well layer 18 has a confinement effect for electrons and does not have a confinement effect for holes 16. Therefore, electrons (injection current 12) are efficiently confined in the well layer 18, while holes are efficiently supplied from the substrate 9 side to the well layer 18, so that the electrons are positive in the well layer 18. Recombination is possible without being limited by the number of holes 16. Therefore, the intensity of light emission accompanying recombination can be further increased.
[0032]
<Embodiment 3>
In the present embodiment, the function and thickness of the upper barrier layer 17 will be described. The upper barrier layer 17 formed in the light-emitting medium 4 for optical recording exemplified in the first to second embodiments (FIGS. 2 and 4) prevents the electrons in the confinement layer (well layer 18) from diffusing to the medium surface. To work. When the upper barrier layer is thin, electrons that are injected to excite do not lose the initial energy, ballistically pass through the upper barrier layer and enter the well layer at a high rate. On the contrary, it becomes easy to permeate the medium surface due to the effect. Electrons emitted to the surface of the medium are lost by recombination with holes without emitting light through surface levels and the like. Therefore, the light emission efficiency decreases.
[0033]
Conversely, when the upper barrier layer is thick, electrons in the well layer hardly pass through the upper barrier layer and dissipate to the surface, but when it is too thick, the injected electrons are elastic while passing through the upper barrier layer. The direction changes due to scattering, and the rate of energy relaxation to the bottom of the conduction band increases due to inelastic scattering. The electrons whose energy has been relaxed to the bottom of the conduction band of the upper barrier layer diffuses in the upper barrier layer and is divided into the confinement layer side and the medium surface side.
[0034]
Therefore, the number of electrons injected into the confinement layer itself is reduced, and the recombination emission intensity in the confinement layer is reduced. Further, when the upper barrier layer is thicker, the distance between the condensing probe and the confinement layer that is the light emitting source is increased, so that the amount of light entering the condensing probe is reduced and the amount of condensing is reduced. From these tendencies, there is an optimum value for the thickness of the upper barrier layer. As a specific embodiment, the case where the upper barrier layer is formed of InGaP will be described. The light emission intensity from the well layer increases as the thickness of the upper barrier layer increases, and the light reception intensity is maximum at about 9 to 10 nm. It becomes. It has been experimentally obtained that when the thickness of the upper barrier layer is further increased, the detected light quantity is suddenly decreased. In consideration of a margin for actually producing a light emitting medium, the thickness of the upper barrier layer is preferably in the range of 5 to 20 nm, and the light emission sharply decreases below 5 nm, and the detected light intensity decreases when exceeding 20 nm. Therefore, it is not preferable. A more preferable range in which high emission intensity can be obtained is approximately 8 to 15 nm.
[0035]
<Embodiment 4>
In the present embodiment, a light-emitting medium having the band structure shown in FIG. 7 will be described with respect to the light-emitting medium for optical recording having the structure shown in FIG. In FIG. 6, 1 is a conductive condensing probe, 20 is a gap between the probe and the surface of the medium, 4 is a light emitting medium for optical recording, 7 is an electrode layer, 9 is a substrate, 12 is an injection current, 13 is detection light, 16 is Holes, 17 is an upper barrier layer, 18 is a well layer (electron confinement layer), 18-1 is a second well layer (quantum well layer), 19 is a bottom barrier layer, 19-1 is a potential gradient region of the bottom barrier layer It is. In FIG. 7, the injection current 12 passes through the second well layer 18-1 to become detection light 13 and flows in the direction of the conductive condensing probe 1, and the holes 16 pass through the second well layer 18-1. And recombine with the electrons confined in the second well layer 18-1.
[0036]
In the present embodiment, in the well layer 18, a second well layer (quantum well layer) 18-1 having a thickness smaller than an electron size and a smaller energy level than an adjacent region, and the quantum well layer A light-emitting medium constituted by two portions (corresponding to the well layer 18 in the above embodiment) that are thicker and have a larger band gap will be described.
[0037]
In this structure, the injected electrons once enter the well layer 18, but the quantum well layer (second well layer 18-1) therein has a higher energy level. In the quantum well layer. This quantum well layer is smaller than the pit size in the plane and has a slight thickness fluctuation. This fluctuation prevents the electrons from diffusing in the in-plane direction and functions to confine the electrons in the in-plane direction. In addition, since the electrons confined in the quantum well layer have a high density, the light emission efficiency is increased. Therefore, according to the present embodiment, there is an effect that the light emission efficiency can be remarkably improved by capturing electrons injected into the light emitting medium in the well layer in a wide range and further concentrating them in the quantum well layer.
[0038]
In the above description of the embodiment, the case of injecting electrons has been described. However, even in the case of injecting holes, the present invention can be similarly applied by replacing the electrons and holes. In addition, when the light emitting medium is excited by injecting light such as near-field light, electron-hole pairs that recombine light are generated directly in the well layer by light, and Considering that when the rate at which electrons shunt through the upper barrier layer and enter the well layer sometimes corresponds to the decrease in the rate at which light is absorbed by the upper barrier layer and excites the well layer, The present invention can be similarly applied to photoexcitation.
[0039]
【The invention's effect】
According to the light-emitting medium for optical recording and the optical recording apparatus of the present invention, the light-emitting medium having a material and a structure capable of efficiently concentrating carriers contributing to light emission in a nanometer-sized minute region of the light-emitting medium is used. Therefore, it is possible to achieve a terabit-class ultra-high density optical recording apparatus that realizes effective light emission and light reception.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the structure of an optical recording apparatus using a light emitting medium for optical recording exemplified in Embodiment 1 of the present invention.
FIG. 2 is a schematic diagram showing the structure of the light-emitting medium exemplified in Embodiment 1 of the present invention.
FIG. 3 is a diagram showing an energy band structure of the light emitting medium shown in FIG. 2 according to Embodiment 1 of the present invention.
FIG. 4 is a schematic diagram showing a structure of a light emitting medium exemplified in Embodiment Mode 2 of the present invention.
5 shows an energy band structure of the light emitting medium shown in FIG. 4 according to Embodiment 2 of the present invention. FIG.
6 is a schematic diagram illustrating a structure of a light-emitting medium exemplified in Embodiment 4 of the present invention. FIG.
7 shows an energy band structure of the light emitting medium shown in FIG. 6 according to Embodiment 4 of the present invention. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Conductive condensing probe 2 ... Optical fiber 3 ... Transparent conductive film 4 ... Light-emitting medium 5 for optical recording ... Surface protective layer (or upper barrier layer)
6 ... Luminescent material 6a ... Signal light generation area (recording unit: pit)
6b ... Signal light non-generation region 7 ... Electrode layer 8 ... Light reflection layer 9 ... Substrate 10 ... Photodetector 11 ... Signal processing circuit 12 ... Injection current 13 ... Detection light 14 ... Near field light 15 ... Bias power supply 16 ... Hole 17 ... Upper barrier layer 18 ... Well layer (electron confinement layer)
18-1 ... Second well layer (quantum well layer)
19 ... Bottom barrier layer 19-1 ... Potential gradient region 20 of bottom barrier layer ... Gap between probe and medium surface

Claims (11)

A light-emitting medium for optical recording that generates light by excitation from the outside, and the light-emitting medium for optical recording is constituted at least by a pair of barrier layers for electrons and an electron confinement layer sandwiched between these barrier layers ,
The light-emitting medium for optical recording , wherein the barrier layer disposed below the electron confinement layer among the barrier layers of the light-emitting medium has a smaller barrier effect against holes than a barrier effect against electrons .   2. The light-emitting medium for optical recording according to claim 1, wherein the electron confinement layer of the light-emitting medium is made of AlGaAs having an Al composition ratio of 0.4 or less, and the barrier layer disposed below the confinement layer is made of AlAs. A light-emitting medium for optical recording, wherein the Al concentration is continuously changed between the confining layer made of AlGaAs and the AlAs barrier layer below the confining layer.   2. The light-emitting medium for optical recording according to claim 1, wherein the barrier layer disposed on the surface side of the electron confinement layer among the barrier layers of the light-emitting medium is made of an InGaP compound, and the thickness of the barrier layer is 5 nm to 20 nm. A light-emitting medium for optical recording, characterized by being in a range.   2. The light-emitting medium for optical recording according to claim 1, wherein the barrier layer disposed on the surface side of the electron confinement layer among the barrier layers of the light-emitting medium is made of an InGaP compound, and the thickness of the barrier layer is 8 nm to 15 nm. A light-emitting medium for optical recording, characterized by being in a range.   2. The light-emitting medium for optical recording according to claim 1, wherein the electron confinement layer of the light-emitting medium has an electron confinement smaller than the band gap of the electron confinement layer and having a layer thickness smaller than the electron wavelength. A light-emitting medium for optical recording, comprising a layer portion. In the optical recording luminescent medium according to any one of claims 1 to 5, the optical recording emitting medium nanometers for limiting the movement of small mutually current than the size of the recording unit in a plane Subdivided into microscopic sections of size, the microcompartments are composed of a signal light generating region that generates light by current and a signal light non-generating region that does not generate signal light, and the light-emitting medium has at least a protective layer on the surface, A light-emitting medium for optical recording, which is held by a substrate. The light-emitting medium for optical recording according to any one of claims 1 to 6 , wherein a material that reflects light is provided on the substrate, or is configured to reflect light. A light emitting medium for optical recording. The light emission medium for optical recording according to any one of claims 1 to 7 , wherein an electrode layer is provided on the substrate or a conductive substrate is used. Medium. The light-emitting medium for optical recording according to any one of claims 1 to 8 , and a conductive collection having conductivity and light transmission, which excites a nanometer-sized region in the light-emitting medium to generate light. An optical recording apparatus comprising at least an optical probe, wherein the light emitting medium and the conductive condensing probe are held at a distance in a range where a current flows between them, or held in contact with each other, and the conductive probe An optical recording apparatus, wherein a current is passed between a tip of a condensing probe and the light emitting medium, and light emitted by the electric current is condensed by a conductive condensing probe. It according to claim 9, the distance between the conductive condensing probe and the light emitting medium is held at a distance which the current can be reached by a tunnel effect, the current allowed to rise to emission in the light emitting medium is a current flowing through the tunnel effect An optical recording apparatus characterized by the above. 10. The optical recording apparatus according to claim 9, wherein the current that causes the light emission medium to emit light when the conductive condensing probe and the light emitting medium are in contact with each other is a current that flows through the contact.

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