JP4621895B2 - Access recordable optical memory - Google Patents

Description

  The present invention relates to an optical memory capable of optically reading predetermined information stored in advance, and more particularly to an access memory capable of recording an access suitable for recording access from an unspecified person and an access recording method for the optical memory.

Conventionally, optical memories have played an important role in ultra-large capacity information communication technology. Particularly in recent years, an optical memory is expected to have an ultra-high density exceeding 1 Tbps / inch ² .

  An optical memory currently in practical use records information by irradiating an optical recording medium with a laser beam condensed to the diffraction limit and applying thermal or magnetic modulation to the recording layer. Further, when the recorded information is read, it is executed by detecting a change in reflected light intensity or polarization state modulated by the recording mark.

  In particular, in order to cope with the increase in the amount of information surrounding information devices such as computers in recent years, a large-capacity optical memory that exceeds the limit of recording density is required.

As a promising next-generation large-capacity optical memory, a so-called near-field optical memory that records and reproduces information using near-field light has been proposed (see, for example, Patent Document 1). ). In addition, a near-field light probe is used to locally exude near-field light from such a near-field light memory (see, for example, Patent Document 2).
JP 2000-021005 A Japanese Patent Laid-Open No. 10-082792

  By the way, there are cases where information (hereinafter referred to as security information) that should be kept confidential, such as personal information and internal confidential matters of companies, is stored in such an optical memory. Since optical memory is a device that reads information through optical access, when such security information is leaked, the optical memory for the optical memory can be obtained from an external party who has no obligation to maintain confidentiality (hereinafter, unspecified persons). In general, there is always a certain access.

  However, in the nano-scale optical memory below the diffraction limit of light as described above, it is physically difficult to reliably record access from such unspecified persons, thus ensuring the confidentiality of information. There was a problem that it was impossible.

  Further, in addition to ensuring the confidentiality of information as described above, it is necessary to record the access history on the digital data recorded in the optical memory from the viewpoint of copyright and privacy protection.

  Therefore, the present invention has been devised in view of the above-mentioned problems, and in a nanoscale optical memory below the diffraction limit, such access from an unspecified person is left as a trace to be stored in the optical memory. It is an object of the present invention to provide an access recordable optical memory and a method for recording access to the optical memory, which can guarantee the confidentiality of the recorded information.

  An access recordable optical memory according to the present invention comprises nanostructures arranged as non-rewritable storage bits, and is based on a difference in shape of the nanostructures or a difference in scattering cross section of light irradiated on them. An information storage layer that is optically readable, and an access recording medium that is disposed close to the back side of the light incident surface of the information storage layer and records optical access to the information storage layer It is characterized by providing.

  The access-recordable optical memory according to the present invention comprises nano-particles as non-rewritable storage bits arranged at intervals equal to or less than the diffraction limit of light, and one or more memories based on the return light of the irradiated light. An information storage layer capable of optically reading information with one bit as a unit and a back side of the information storage layer on the light incident side to record optical access to the information storage layer And an access recording medium.

  In the method of recording access to the optical memory according to the present invention, the information storage layer of the optical memory in which the nanostructures as non-rewritable storage bits are arranged is irradiated with light, whereby the difference in shape of the nanostructures or Information is optically read based on the difference in the scattering cross-sections of the light applied to them, and the information storage layer is accessed by an access recording medium disposed close to the back side of the light incident surface of the information storage layer. It is characterized by recording optical access.

  The access recording method to the optical memory according to the present invention returns the data by irradiating the information storage layer of the optical memory in which nanoparticles as non-rewritable storage bits are arranged at intervals equal to or less than the diffraction limit of light. Optically reading information with one or more storage bits as a unit based on light, and optically accessing the information storage layer by an access recording medium disposed on the back side of the light incident side of the information storage layer It is characterized by recording various accesses.

  In the present invention, by irradiating light to the information storage layer of the optical memory in which the nanostructures as the non-rewritable storage bits are arranged, the difference in the shape of the nanostructures or the scattering of the light irradiated to them. Information is optically read based on the difference in cross-sectional area, and optical access to the information storage layer is recorded by an access recording medium disposed close to the back side of the light incident surface of the information storage layer.

  Further, in the present invention, by irradiating the information storage layer of the optical memory in which the nano-particles as the non-rewritable storage bits are arranged at intervals equal to or less than the diffraction limit of the light, one or more based on the return light The optical access to the information storage layer is recorded by an access recording medium disposed on the back side of the information storage layer on the light incident side.

  Accordingly, in the present invention, it is possible to simultaneously read information assigned to the nanostructure or nanoparticle and to record traces on the access recording medium, and to read security information by an unspecified person. Thus, the confidentiality of the information stored in the optical memory can be ensured.

  In addition, according to the present invention, the access history can be recorded in the optical memory as hardware, and the copyright and privacy of the digital data recorded in the optical memory can be protected. Furthermore, in an optical memory to which the present invention is applied, it is possible to record a history of the number of accesses by applying a certain device to an access recording medium or the like.

  Hereinafter, an access recording method for recording an access from an unspecified person as a trace will be described in detail with reference to the drawings as the best mode for carrying out the present invention.

  FIG. 1 conceptually shows an access recording method to which the present invention is applied. In this access recording method, when an unspecified person reads the security information stored in the optical memory 1, the optical memory 1 is optically accessed, but recording is performed by leaving this as a trace. . In the optical memory 1, a plurality of nanostructures 11 as non-rewritable storage bits are arranged, and the above-described optical access is performed by irradiating propagating light thereto. Become.

  FIG. 2 is a perspective view of a first embodiment of an optical memory 1 to which the present invention is applied. 3A and 3B are front views of the optical memory 1, and FIG. 4 is a side view of the optical memory 1. FIG.

  In the first embodiment, the nanostructure 11 is constituted by a substantially triangular nanometer-size flat plate having three corners formed therein. The corners need not be sharpened and may be rounded. As shown in FIG. 3, nanostructures 11a and nanostructures 11b are arranged in the x direction. The x direction and the perpendicular direction are hereinafter referred to as the y direction. One memory bit is formed by bringing the corners of two nanostructures 11 close to each other. As shown in FIG. 4, propagating light is applied to the nanostructure 11 from above. The surface irradiated with propagating light in the nanostructure 11 is referred to as a light incident surface 21a. A layer in which the nanostructures 11 are arranged is referred to as an information storage layer 21.

  The nanostructure 11 is made of a metal such as gold, silver, aluminum, copper, chromium, or platinum. As the nanostructure 11, for example, when a silicon substrate or a GaAs, GaN, or GaP-based semiconductor is used, the nanostructure 11 is manufactured using, for example, a method described in JP-A-2005-142444. Also good.

  Incidentally, in this nanostructure 11, as shown in FIG. 3A, two nanostructures 11a in which no hole is formed in the center constitute one memory bit, or as shown in FIG. 3B. Thus, one memory bit is constituted by the nanostructure 11b having a hole formed in the center.

The access recording medium 12 is disposed close to the back side 21b of the light incident surface 21a in the information storage layer 21. This access recording medium 12 has a phase change such as InAgSbTe, TeGeSb, TeGeSbSn, SbSe, BiTe, Te-alloy, Se-alloy, (Ag, Bi, Ge, In, Pb, Sb, Se, Sn, Te). It consists of materials, magnetic materials such as TbFeCo, TbFeCoCr, TbFeCoSi, GdFeCo, and NdFeCo used for magneto-optical disks, and non-rewritable materials such as Ag _x O.

  The access recording medium 12 is disposed in a state where a gap 23 is formed between the access recording medium 12 and the information recording layer 21, and is disposed in parallel with the nanostructure 11. The gap 23 between the access recording medium 12 and the information storage layer 21 is optimized based on a mechanism to be described later, but it is generally desirable that the gap 23 be configured in the range of 5 nm to l / 4. The reason is that it is difficult to control the head at 5 nm or less, and the proximity effect is lost when it is 1/4 or more. Considering the use of wavelengths up to the microwave band, the maximum is preferably l / 4.

  A method of recording an unspecified person's access using the optical memory 1 having such a configuration will be described.

  First, each nanostructure 11 is irradiated with propagating light. The intensity of the return light of the propagating light thus irradiated varies depending on the difference in the shapes of the nanostructures 11a and 11b. That is, the security information “0” or “1” in the digital signal is read by utilizing the difference in properties such as the intensity of the return light generated due to the difference in the shapes of the nanostructures 11a and 11b.

  For example, information “0” as a digital signal is assigned as the nanostructure 11a, and information “1” as a digital signal is assigned as the nanostructure 11b. In such a case, when information of the digital signal “0” is stored at a predetermined address of the optical memory 1, the nanostructure 11 a is produced at the address, and the information of the digital signal “1” is stored at the predetermined address of the optical memory 1. Is stored, the nanostructure 11b is produced at the address. Next, when reading a digital signal, the nanostructure 11 is spot-adjusted and irradiated with propagating light. As a result, when the nanostructure 11a can be read, the digital signal “0” assigned thereto is obtained, and when the nanostructure 11b can be read, the digital signal “1” assigned thereto is obtained. get.

  In this manner, information can be optically read based on the difference in shape of the nanostructure 11.

  Incidentally, reading of information from the nanostructure 11 is not limited to the case of executing based on the difference in shape. For example, the information may be optically read based on the difference in the scattering cross section of the light irradiated on the nanostructure 11. Since the nanostructure 11a and the nanostructure 11b have different shapes from each other, the distributions of scattered light based on the propagating light irradiated on them are different from each other. That is, by detecting the difference in scattering cross section between the nanostructure 11a and the nanostructure 11b, the digital signal “0” assigned to the nanostructure 11a or the nanostructure 11b is assigned. It is possible to read the digital signal “1”.

  In the optical memory 1, the access of an unspecified person can be recorded simultaneously with the reading of information as a digital signal assigned to the nanostructure 11. When the information assigned to the nanostructure 11 is read, the nanostructure 11 is always irradiated with light. As a result, plasmons are induced in the nanostructure 11 and a strong electric field is induced in the gap 13. When the nanostructure 11 is configured as one substantially triangular nanostructure, the electric field can be enhanced at the tip of the approximately triangular shape.

  The point where a strong electric field is generated in the gap 13 of the nanostructure 11 is a physical property that has been clarified in the past. For example, “T. Matsumoto, T. Shimano, H. Saga, H. Sukeda, J. Appl. Phys., Vol. 95, No. 8, 15 April 2004 ”.

  When the electric field strength is increased in the gap 13 of the nanostructure 11, a region having a high electric field strength reaches the access recording medium 12 as shown in FIG. As a result, the physical properties of the access recording medium 12 change based on the energy generated by the enhanced electric field, and as a result, a trace 45 is formed as shown in FIG. The trace 45 is reliably formed on the access recording medium 12 by optimizing the size of the gap 23 between the access recording medium 12 and the information storage layer 21 to such an extent that the region where the electric field strength is strong. Is possible.

  That is, in the optical memory 1 to which the present invention is applied, it is possible to simultaneously read out information assigned to the nanostructure 11 and record the trace 45 on the access recording medium 12. For this reason, when an unspecified person reads out the information assigned to the nanostructure 11, the nanostructure 11 is always irradiated with light. The trace 45 is recorded on the access recording medium 12. Incidentally, by identifying the trace 45 later, it becomes possible to identify the access of the unspecified person to the optical memory 1.

  In the above-described embodiment, the case where two substantially triangular nanostructures 11 are arranged in the x direction and configured as one memory bit has been described as an example. However, the present invention is limited to this case. It is not a thing. For example, one nanostructure 11a and one nanostructure 11b may each be configured as one storage bit. This is because even if it is composed of one nanostructure, a portion where the electric field is enhanced occurs at any one of the corners, and this can be left as a trace 45 on the access recording medium 12.

  In addition, the nanostructure 11 may be formed in any polygonal shape including a quadrangle and a pentagon, except when the nanostructure 11 is configured in a substantially triangular shape. In other words, any shape may be used as long as the shape gradually decreases toward the portion defined by 13 (not referred to as a gap when the number of the structures 11 is one). The shape of the nanostructure 11 may be a circle, an ellipse, or any other irregular shape. That is, the nanostructure 11a and the nanostructure 11b may be configured in any shape as long as the shapes are different from each other.

  Next, a second embodiment of the present invention will be described.

  In the second embodiment, as shown in FIG. 6 (a), an information storage layer 61 in which a plurality of types of nanoparticles 6 having different sizes are arranged, and optical access to the information storage layer 61 are performed. It is embodied as an optical memory 2 provided with an access recording medium for recording.

  In the information storage layer 61, nanoparticles 6 as non-rewritable storage bits are arranged at intervals equal to or less than the light diffraction limit. The information storage layer 61 is irradiated with propagating light from the direction shown in the figure. The side on which the propagation light is irradiated in the information storage layer 61 is hereinafter referred to as a light incident side 6a.

  The nano fine particles 6 are semiconductor fine particles, metallic fine particles, magnetic fine particles, or the like. The metallic fine particles are made of, for example, a material such as Au. The nanoparticle 6 can be charged with an electric dipole. Through the presence or absence of a dipole in each nanoparticle 6, it is possible to record “0” or “1” information as a digital signal.

  Further, in the information storage layer 61, for example, a region where the nano fine particles 6 made of semiconductor fine particles, metallic fine particles, or magnetic fine particles are formed, and a region where the nano fine particles 6 are not formed may be created. The information “0” or “1” in the digital signal is recorded through the presence / absence of the nanoparticles.

  Moreover, as this nanoparticle 6, you may make it utilize a quantum dot, for example. According to this quantum dot, single electrons (excitons) can be controlled based on discrete energy levels formed by confining excitons in three dimensions. As a result, in this quantum dot, the energy level of the carriers becomes discrete by the exciton confinement system, and the state density can be sharpened in a delta function.

  FIG. 6B shows an example in which a plurality of types of quantum dots 6_1 to 6_4 having different sizes are regularly arranged. The size of these quantum dots 6 is configured to gradually increase from quantum dot 6_1 to quantum dot 6_4. The quantum dots 6_1 are arranged on the outermost circumference, the quantum dots 6_2 are arranged on the adjacent inner circumference side, and further the quantum dots 6_3 are arranged on the inner circumference side. Dots 6_4 are formed.

  The access recording medium 62 is disposed on the back side of the light incident surface 6 a in the information storage layer 61. The access recording medium 62 may be made of, for example, a photosensitive photoresist, and may change the physical properties by receiving light and be able to remove the photosensitive portion by being immersed in a so-called developer.

  With respect to a method for recording access of an unspecified person by the optical memory 2 having such a configuration, a case where a plurality of types of quantum dots 6_1 to 6_4 as shown in FIG. Explain.

  When propagating light is irradiated to the quantum dot 6_1, the light energy is condensed to the center quantum dot 6_4 via the quantum dot 6_2 and the quantum dot 6_3. For this condensing mechanism, for example, the disclosure technique of the following document may be referred to (T. Kawazoe, K. Kobayashi, and M. Ohtsu, “The optical nano-fountain: a biomimetic device that concentrates optical energy in a nanometric region, ”Appl. Phys. Lett. 86, 103102-1-3 (2005).).

  Here, as shown in FIG. 7A, attention is focused on the energy transfer mechanism for the quantum dot 6_2 adjacent to the two quantum dots 6_1.

Energy level E in each quantum dot _{6_1,6_2 (n x, n y,} n z) is the mass of the particle and m, also the side length of the quantum dot when is L, the following equation (1) Defined.

E (n _x , n _y , n _z ) = h ² / 8π ² m (π / L) ² (n _x ² + _ny ² + n _z ² ) (1)

In the present invention, depending on the shape and material of the quantum dot, in addition to the energy level E (n _x , n _y , n _z ) defined by this equation (1), other general energy In some cases, level formulas may apply.

Based on this equation (1), E (n _x , n _y , n _z ) of each quantum dot 6_1, 6_2 is calculated. Here, when the side length ratio between the quantum dot 6_1 and the quantum dot 6_2 is about 1: √2, the energy level in the quantum dot 6_1 is (1, 1, 1) as shown in FIG. ) Is equal to E (211) when the energy level of the quantum dot 6_2 is (2,1,1). That is, the energy level (1, 1, 1) in the quantum dot 6_1 and the energy level (2, 1, 1) in the quantum dot 6_2 are in a relationship in which the excitation energy levels of the excitons resonate.

  For this reason, by forming the quantum dots 6_1 and 6_2 having different side length ratios, the quantum levels based on the equation (1) can be made substantially equal, and by causing resonance between them, the size can be increased. Excitons can be injected from the small quantum dot 6_1 to the large quantum dot 6_2. In other words, by making the volumes (sizes) different between the quantum dots, excitons can be transmitted between them, and hence resonance energy transfer can be realized.

  By moving excitons from quantum dots 6_2 to 6_3 to quantum dots 6_4 based on the same mechanism, energy transfer can be realized.

  The excitons finally injected into the quantum dot 6_4 are emitted as light after transiting to the lower level E (111). As a result, light is emitted from the quantum dots 6_4, and the access recording medium 62 is exposed in response to this, and a so-called photosensitive region in which physical properties such as a refractive index are changed in the access recording medium 62. Will be formed.

  When such a photosensitive region is formed, the appearance changes when the optical memory 2 is observed with an optical microscope or the like. As a result, it is possible to identify whether or not a photosensitive area is formed, and as a result, it is possible to record the optical access of the optical memory 2 by an unspecified person as a trace.

  Note that the light emitted from the quantum dot 6_4 is based on the relaxation from the quantum level E (111) in the quantum dot 6_4, and the relaxation from the energy level can be combined with the propagating light. For this reason, the light emitted from the quantum dot 6_4 can be considered in the same manner as normal propagation light. However, in the optical memory 1 to which the present invention is applied, the light emitted from the quantum dot 6_4 is absorbed by the access recording medium 62, and therefore, the optical memory 1 is not limited to the property of propagating far. That is, the light emitted from the quantum dot 6_4 does not have to be so-called propagating light, and may be light that is locally dissipated.

  In order to expose the access recording medium 62 only to the light emitted from the large quantum dots 6_4, the wavelength of the emitted light is made different from the wavelength of the irradiation light, and the access recording medium 62 only has the wavelength of the emitted light. It is desirable that the material is composed of a photosensitive material.

  Further, in the optical memory 1 composed of the quantum dots 6_1 to 6_4, when reproducing the stored information, for example, the configuration of the AND operation element as disclosed in JP 2006-023505 A is used. You may make it incorporate in at least one part of quantum dot 6_1-6_4. Then, the reproduction capacity of digital data may be obtained by adopting a form in which “0” or “1” is detected at the frequency of the gate output in the AND operation element.

  The trace recording method described above is merely an example, and it is needless to say that other methods may be substituted.

  A simulation was performed to verify the reading of information from the optical memory 1 and the recording of the trace 45. In this simulation, for example, as shown in FIG. 8, a model in which two nanostructures 11b (11a) are arranged in the x direction was created. In this model, the material of the nanostructure 11b (11a) is Ag, the width of the gap 13 is 5 nm, and the length of the nanostructure 11b (11a) in the x direction is 215 nm. The radius of curvature of the corner is 20 nm, the angle of the corner is 60 °, and the thickness of the nanostructure 11b is 30 nm. Moreover, about the hole 51 formed in the nanostructure 11b, the center position is a position spaced 150 nm away from the center of the gap 13 in the x direction, and the radius is 50 nm. In contrast, the nanostructure 11a is a model in which the holes 51 are not formed.

  When such a nanostructure 11b (11a) is irradiated with light having a wavelength of 830 nm and a polarization direction in the x-axis direction, the electric field strength generated in the gap 23 and the x-direction of the electric field strength peak are respectively shown. The half width in the y direction was obtained by calculation.

  FIG. 9 shows the electric field intensity distribution in a plane separated from the metal surface constituting the nanostructure 11 by 5.4 nm. 9A shows the electric field strength distribution of the nanostructure 11a, and FIG. 9B shows the electric field strength distribution generated in the nanostructure 11b. A strong electric field strength peak was generated in gap 13. The peak electric field strength in the nanostructure 11a is about 250 times the electric field strength of incident light, whereas the peak electric field strength in the nanostructure 11b is the electric field strength of incident light. It was 122 times. That is, the electric field strength generated in the nanostructure 11a is larger than the electric field strength generated in the nanostructure 11b, but is 100 times larger than the electric field strength of the incident light, and the above-described trace 45 is accessed. This difference does not become a barrier in forming on the recording medium 12.

  Full width at half maximum (FWHM) The width of the value at half the intensity of the peak. If the distribution is symmetrical with respect to the value having the peak, the width may be defined by the half width. Not, but generally not, so defined as full width) was about 10 nm in the x direction and about 23 nm in the y direction. This half-width showed the same tendency between the nanostructures 11a and 11b.

  Further, as shown in the graph of FIG. 10, the calculated electric field strength and half-value width are both the magnitude of the electric field strength and the half-value width of the peak of the electric field strength in both the nanostructure 11a and the nanostructure 11b. Were almost equivalent. For this reason, even when propagating light is irradiated to any of the nanostructures 11a and 11b, almost the same electric field enhancement occurs in the nanostructures 11a and 11b. Based on this, the same trace 45 is obtained. It has been shown that you can leave. This means that even when the digital signal “0” or “1” is read, it is recorded as the trace 45 and can be identified afterwards.

  FIG. 11 shows the result of calculating the distribution tendency of scattered light of the nanostructure 11a and the nanostructure 11b by calculation. In the nanostructure 11a in which no hole is formed in the center, light is scattered in a wider region as compared with the nanostructure 11b in which a hole is cut in the center. When the difference in scattering cross section between the nanostructure 11a and the nanostructure 11b was actually compared, the scattering cross section of the nanostructure 11a that scatters light in a wider region is about twice that of the nanostructure 11b. Met.

  That is, the difference in scattering cross section between the nanostructure 11a and the nanostructure 11b is detected in a region size substantially equal to that of the nanostructure 11 as a whole, thereby being assigned to the nanostructure 11a. It is possible to read digital signals.

  Next, the relationship between the increase in electric field strength and the ON / OFF ratio when only the radius of the hole 51 formed in the nanostructure 11b was changed to 10 to 70 nm was analyzed. As a result, as shown in FIG. 12, the electric field strength tends to increase as the radius of the hole 51 is decreased. In contrast, the ON / OFF ratio tended to increase as the radius of the hole 51 was increased.

  From these tendencies, it is necessary to optimize the radius of the hole 51 in order to improve the ON / OFF ratio while securing a certain electric field strength. In order to maintain both the electric field strength and the ON / OFF ratio in a good balance, it is desirable that the radius of the hole 51 be 50 nm.

It is a conceptual diagram of the access recording method to which this invention is applied. 1 is a perspective view of an optical memory according to a first embodiment to which the present invention is applied. It is a front view of the optical memory to which the present invention is applied. 1 is a side view of an optical memory to which the present invention is applied. It is a figure for demonstrating operation | movement of this invention. It is a figure shown about 2nd Embodiment in the optical memory to which this invention is applied. It is a figure for demonstrating the case where a photosensitive area | region is formed in an access recording medium. It is a figure for demonstrating a simulation model. It is a figure which shows electric field strength distribution of a nanostructure. It is a figure shown about the comparison result of the magnitude | size of the calculated electric field strength and a half value width. It is a figure which shows the result of having calculated | required the distribution tendency of the scattered light of a nanostructure by calculation. It is a figure which shows the relationship between the amount of electric field strength increase, and ON / OFF ratio when changing only the radius of the hole formed in the nanostructure to 10-70 nm.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Optical memory 6 Nanoparticle 11 Nano structure 12 and 62 Access recording medium 13 Gap 21 and 61 Information storage layer 23 Gap

Claims (13)

By arranging nanostructures as non-rewritable memory bits, information can be optically read based on the difference in the shape of the nanostructures or the difference in the scattering cross section of the light applied to them. An information storage layer;
An access recordable optical memory, comprising: an access recording medium that is disposed close to a back side of a light incident surface of the information storage layer and records optical access to the information storage layer. 2. The access recordable optical memory according to claim 1, wherein the information storage layer forms the one storage bit by a substantially triangular nanostructure. 3. The access recordable optical memory according to claim 2, wherein the information storage layer creates the difference in shape through the presence or absence of a hole to be formed in the nanostructure. 3. The information storage layer according to claim 2 , wherein corners of two nanostructures are brought close to each other to form one storage bit, or one nanostructure forms one storage bit. 3. An optical memory capable of access recording according to 3. The access recording medium is made of a material that changes in physical properties based on energy by an electric field generated through a corner portion of the nanostructure during optical access to the information storage layer, and further in the electric field generation region. The access recordable optical memory according to any one of claims 1 to 4, wherein the optical recording memory is close to the information storage layer up to a position to reach. 3. When light is irradiated to the substantially triangular nanostructure, plasmon is induced in the metal or semiconductor nanostructure, and the electric field at the tip of the approximately triangular shape is enhanced. Access recordable optical memory. Nano-particles as non-rewritable memory bits are arranged at intervals less than the diffraction limit of light, and information with one or more memory bits as one unit is optically determined based on the return light of the light irradiated to them. A readable information storage layer;
An access recordable optical memory, comprising: an access recording medium disposed on the back side of the light incident side of the information storage layer for recording optical access to the information storage layer. 8. The access recordable optical memory according to claim 7, wherein the information storage layer has the storage bit as semiconductor fine particles, metallic fine particles, or magnetic fine particles formed on the access recording medium. 9. The access recordable optical memory according to claim 7, wherein the access recording medium is sensitive to light emitted from the nanoparticles based on the irradiated propagation light. By irradiating light to the information storage layer of the optical memory in which the nanostructures as the non-rewritable memory bits are arranged, the difference in the shape of the nanostructures or the difference in the scattering cross section of the light irradiated to these To read information optically based on
An access recording method for an optical memory, characterized in that optical access to the information storage layer is recorded by an access recording medium disposed close to the back side of the light incident surface in the information storage layer. At the time of optical access to the information storage layer, the access recording medium is brought close to a position where the electric field generated via the nanostructure is reached, and the access recording medium is moved based on the energy of the electric field. The optical memory access recording method according to claim 10, wherein the optical access is recorded by changing physical properties. By irradiating light to the information storage layer of the optical memory in which nano-particles as non-rewritable storage bits are arranged at intervals less than the diffraction limit of light, one unit of one or more storage bits is obtained based on the return light To read the information optically,
An access recording method for an optical memory, characterized in that optical access to the information storage layer is recorded by an access recording medium disposed on the back side of the light incident side of the information storage layer. The method of recording an access to an optical memory according to claim 12, wherein the access recording medium is exposed to light emitted from the nanoparticles based on the irradiated propagation light.

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