JP2017162525A - Hologram recording playback system and hologram recording playback method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hologram recording playback system capable of improving reliability of information recording and acceleration of the same, and a hologram recording playback method.SOLUTION: In a hologram recording playback system and a hologram recording playback method of the present invention, when hologram is recorded, by signal light in a prescribed polarization direction, recording playback reference light in a same polarization direction as the signal light, and verification reference light whose polarization direction is orthogonal to the polarization direction of the signal light being simultaneously radiated onto a recording medium, an interference fringe pattern of the signal light and the recording playback reference light is recorded as hologram and verification processing is performed with the recorded hologram being reproduced by the verification reference light.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hologram recording / reproducing apparatus and a hologram recording / reproducing method. More specifically, the present invention relates to a hologram recording / reproducing apparatus and a hologram recording / reproducing method for constructing a large-capacity optical memory by multiplexly recording a two-dimensional digital bit pattern as a hologram on a recording medium.

2. Description of the Related Art Conventionally, hologram recording / reproducing apparatuses that record and reproduce digital information two-dimensionally using holograms have been proposed. In a hologram recording / reproducing apparatus, a signal light carrying digital information (data information) modulated by a spatial light modulator composed of a plurality of pixels is obtained by causing the signal light and a coherent reference light to interfere with each other. Interference fringes are recorded as holograms. When reproducing a hologram recorded on a recording medium, the hologram is irradiated with reference light used for recording to generate diffracted light and recorded as a hologram on an image pickup device such as a CCD. An image of digital information is formed.
In such a hologram recording / reproducing apparatus, for example, an angle multiplex recording method, a spherical reference light shift multiplex recording method, and a speckle reference light multiplex recording method are known as specific methods for multiplex recording of holograms. Yes.

  Thus, a hologram recording / reproducing apparatus is usually required to perform a verify process for confirming whether or not information has been recorded accurately. The verify process is performed by reproducing information (hologram) recorded on the recording medium.

For example, in Patent Document 1, in a hologram recording / reproducing apparatus, after writing necessary information in a recording medium, fixing processing is performed by irradiating the recording medium with fixing light, and information recorded after the fixing processing is recorded. It is described that the verify process is performed.
Further, in Patent Document 2, in a hologram recording / reproducing apparatus, after recording a hologram on a recording medium, only signal light is blocked, and diffracted light from the recorded hologram is received by a light receiving element and recorded on the hologram. It is described that the verification is performed.

JP 2009-145462 A International Publication No. 2006/093196

  As described above, the verify process performed in the conventional hologram recording / reproducing apparatus records information on a predetermined area of the recording medium or the entire recording medium, and then accesses the predetermined area (for example, a track) on which the information is recorded. However, since it is performed by reproducing the recorded information, there is a problem that it takes a long time for the information recording process including the verify process.

  The present invention has been made based on the circumstances as described above, and can improve the reliability of information recording and increase the speed of information recording, and a hologram recording / reproducing apparatus and hologram recording / reproducing It aims to provide a method.

The hologram recording / reproducing apparatus of the present invention includes a recording / reproducing light source, first light separating means for dividing the light from the recording / reproducing light source into signal light and reference light having different polarization directions, and reference light Irradiating the recording medium as signal light carrying data information with second light separating means for dividing the light for use into light for the first reference light and light for the second reference light A signal light irradiating optical system, and irradiating the recording medium with the first reference light light as the recording / reproducing reference light having the same polarization direction as the signal light and the second reference light light as the signal light An optical mechanism comprising a reference light irradiation optical system for irradiating a recording medium as reference light for verification in a polarization direction orthogonal to the polarization direction, and a reproduction light detection optical system for detecting reproduction light from a hologram recorded on the recording medium Have
By simultaneously irradiating the recording medium with the signal light, the recording / reproducing reference light, and the verifying reference light, interference fringes between the signal light and the recording / reproducing reference light are recorded as a hologram and A verification process is performed by reproducing the recorded hologram with the verification reference beam.

  In the hologram recording / reproducing apparatus of the present invention, it is preferable that the power of the verifying reference light is smaller than the power of the recording / reproducing reference light.

Further, in the hologram recording / reproducing apparatus of the present invention, the recording / reproducing reference beam and the verifying reference beam are spherical waves,
A moving mechanism for moving one of the optical mechanism and the recording medium in one direction relative to the other along the surface of the recording medium;
It is preferable that the hologram is configured to be multiplexed and recorded on the recording medium by the shift multiplex recording method.

The hologram recording / reproducing method of the present invention records interference fringes between signal light carrying data information and reference light as a hologram on a recording medium and irradiating the recording medium on which the hologram is recorded with reference light. In a hologram recording / reproducing method for reproducing data information recorded in the hologram,
Simultaneously irradiate the recording medium with signal light having a predetermined polarization direction, recording / reproducing reference light having the same polarization direction as the signal light, and verification reference light having a polarization direction orthogonal to the polarization direction of the signal light. Thus, an interference fringe between the signal light and the recording / reproducing reference light is recorded as a hologram, and a verification process is performed by reproducing the recorded hologram with the verifying reference light.

  In the hologram recording / reproducing method of the present invention, it is preferable that the verifying reference light is irradiated with a power smaller than that of the pre-recording / reproducing reference light.

Further, in the hologram recording / reproducing method of the present invention, spherical waves are used as the recording / reproducing reference beam and the verifying reference beam,
It is preferable to multiplex-record holograms by shift multiplexing.

  According to the hologram recording / reproducing apparatus of the present invention and the hologram recording / reproducing method of the present invention, the verification process is performed by immediately reproducing the hologram recorded on the recording medium. In addition, since it is possible to promptly perform appropriate processing for the write error, the reliability of information recording can be improved, and access to recorded information is not required when performing verification processing. The series of information recording processing including can be accelerated.

It is explanatory drawing which shows the outline of a structure of the signal light irradiation optical system, the reference light irradiation optical system, and the reproduction light detection optical system in the hologram recording / reproducing apparatus of the present invention. It is the schematic for description which shows an example of a principal part structure in the hologram recording / reproducing apparatus of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

  The hologram recording / reproducing apparatus of the present invention includes a signal light having a predetermined polarization direction, a recording / reproducing reference light having the same polarization direction as the signal light, and a verifying reference light having a polarization direction different from that of the signal light and the recording / reproducing reference light. Are simultaneously irradiated onto the recording medium, whereby a hologram formed by interference fringes between the signal light and the recording / reproducing reference light is recorded on the recording medium and the hologram is immediately reproduced by the verifying reference light. Thus, the verify process is performed.

  The hologram recording / reproducing apparatus of the present invention includes a recording / reproducing light source comprising, for example, a laser light source, and first light separating means for dividing light from the recording / reproducing light source into signal light and reference light having different polarization directions. Second light separating means for dividing the light for reference light into light for first reference light and light for second reference light, and the light for signal light as signal light carrying data information A signal light irradiating optical system for irradiating the recording medium, and a first reference light for irradiating the recording medium as a recording / reproducing reference light having the same polarization direction as the signal light and a second reference light Light irradiation optical system that irradiates a recording medium as a reference light for verifying with a polarization direction orthogonal to the recording / reproducing reference light, and reproducing light detection for detecting reproducing light (diffracted light) from a hologram recorded on the recording medium And an optical mechanism having an optical system.

  As shown in FIG. 1, the signal light irradiation optical system receives page data in which digital information is arranged in a two-dimensional array and modulates signal light in a predetermined polarization direction (for example, p-polarized light) by the page data. A spatial light modulator (SLM) 32 that performs the processing, and a signal light focusing objective lens that condenses the signal light Ls and irradiates the recording medium 10 with the light modulated by the spatial light modulator 32 as signal light Ls. 36.

  The reference light irradiation optical system collects the recording reference light Lr1 having the same polarization direction (for example, p-polarized light) as the signal light Ls and the verification reference light Lr2 having a polarization direction (for example, s-polarized light) orthogonal to the polarization direction of the signal light. A reference light collecting objective lens 40 that irradiates and irradiates the recording medium 10 with light is provided. In FIG. 1, the optical paths of the recording reference light Lr1 and the verification reference light Lr2 are distinguished for convenience, but the recording reference light Lr1 and the verification reference light Lr2 are recorded along the same optical path. (Incident conditions are the same).

  The reproduction light detection optical system is configured such that the reproduction light Lg1 emitted from the hologram when the recorded hologram is irradiated with the recording / reproduction reference light Lr1 and the verification reference light Lr2 emitted from the hologram from the hologram. A condensing lens 52 for reproducing light that makes the reproduced light Lg2 emitted incident on the polarized light separating means 50, a polarization separating means 50 that transmits the reflected light Lg1 and reflects the reproduced light Lg2, and a first light on which the reproduced light Lg1 is incident. Imaging element 51a and a second imaging element 51b on which the reproduction light Lg2 is incident. In FIG. 1, the optical paths of the reproduced light are also distinguished for convenience, but the respective reproduced lights Lg1 and Lg2 are incident on the polarization separating means 50 along the same optical path.

In the hologram recording / reproducing apparatus of the present invention, the verifying reference light Lr2 is applied to the recording medium 10 under irradiation conditions with a power (light quantity) smaller than the recording / reproducing reference light Lr1.
The power of the verifying reference light Lr2 is preferably, for example, 1/20 to 1/100 of the power of the recording / reproducing reference light Lr1, and more preferably 1 / th of the power of the recording / reproducing reference light Lr1. The size is about 50 times. Thereby, it is possible to reliably avoid the verification reference light Lr2 from affecting the hologram recording during the hologram recording.

In the hologram recording / reproducing apparatus of the present invention, the method of multiplex recording of holograms on the recording medium 10 is not particularly limited, and a spherical reference light shift multiplex recording method and an angle multiplex recording method using a spherical wave as reference light. Any other method of multiplex recording may be implemented.
Further, in a configuration in which hologram recording is performed by the spherical reference beam shift multiplexing method, for example, spherical reference beam shift multiplexing recording is performed on a certain area of the recording medium 10 to obtain the first shift multiplexed hologram array. Then, in a state where the recording medium 10 is tilted and tilted, spherical reference beam shift multiplex recording is performed on the area where the first shift multiplex hologram sequence is recorded, and the second shift multiplex hologram sequence is multiplexed. A method of recording (tilt shift multiple recording) may be performed. Alternatively, after performing spherical reference beam shift multiplex recording on a certain area of the recording medium 10 to record the first shift multiplex hologram array, the recording medium 10 is rotated and then the spherical reference beam shift multiplexing is performed. A method of performing multiple recording (cross-shift multiplex recording) may be performed in a state where recording is performed and a new shift multiplex hologram sequence is overlapped with a recording region of the shift multiplex hologram sequence in which a part of the recording area is already recorded. .
In a hologram recording / reproducing apparatus in which such a method is performed, for example, a recording medium rotating mechanism that rotates (rotates) the recording medium 10 in a plane along the surface thereof, and the recording medium 10 along the surface thereof. A recording medium moving mechanism for moving the recording medium within a flat plane, or a configuration further including a recording medium tilt mechanism for rotating the recording medium 10 to tilt the surface of the recording medium 10 with respect to the reference plane. That's fine.

The recorded hologram is reproduced almost independently of the polarization direction of the reference light. Therefore, in the hologram recording / reproducing apparatus of the present invention, by utilizing this characteristic, the verifying reference light Lr2 having a polarization direction orthogonal to the polarization direction of the recording / reproducing reference light Lr1 is recorded on the recording medium 10 during recording of the hologram. A verify process is performed by simultaneous irradiation. That is, the recorded hologram is immediately reproduced by the verifying reference light Lr2, thereby verifying the recorded information in real time. In the verification process in the present invention, the reproduction light by the verification reference light Lr2 from the region where the hologram is recorded by the signal light Ls and the recording / reproduction reference light Lr1 is incident on the second image sensor 51b. Thus, it is confirmed that the hologram is recorded in the area. Therefore, a determination process for confirming whether or not the page data (data information) input to the spatial light modulator 32 matches the data information of the reproduction light is not required, but such a determination process is performed. It may be broken.
Then, when it is confirmed that the hologram is not properly recorded (a writing error has occurred) by not detecting the reproduction light of the hologram, for example, writing is performed again in the same location or prepared separately. Appropriate processing such as recording and reproduction is performed in the rewritable area.

  Further, in the hologram recording / reproducing apparatus of the present invention, the recording / reproducing reference light having a sufficiently small amount of light as compared with the recording / reproducing reference light Lr1 used at the time of recording of the hologram is applied to the recording medium 10 to perform the recording. A reproduction light Lg1 having the same polarization direction as that of the recording / reproduction reference light is emitted from a hologram recorded under the same reference light irradiation conditions as the reproduction reference light. The reproduction light Lg1 passes through the polarization separation means 50 and enters the first image sensor 51a, whereby the data information recorded in the hologram is reproduced. At this time, for example, the verifying reference light is also applied to the recording medium 10, and the reproduction light Lg2 is emitted from the hologram. However, the power (light quantity) of the verification reference light Lr2 is small, and the reproduction light Lg2 has a polarization direction different from that of the reproduction light Lg1, so that it is reflected by the polarization separation means 50 and enters the second image sensor 51b. Is done. Accordingly, it is possible to avoid the verification reference light Lr2 from affecting the reproduction of the hologram during the reproduction of the hologram.

  Hereinafter, specific examples of the hologram recording / reproducing apparatus of the present invention will be described with reference to the drawings.

FIG. 2 is an explanatory schematic diagram showing an example of the configuration of the main part of the hologram recording / reproducing apparatus of the present invention.
In this hologram recording / reproducing apparatus, for example, a transmissive disk-shaped device is used as the recording medium 10, and a hologram is multiplexed and recorded on the recording medium 10 by, for example, a spherical reference light shift multiplexing method. An optical mechanism for irradiating the recording medium 10 with the carried signal light and spherical reference light and a recording medium driving mechanism (not shown) are provided.

The optical mechanism splits the recording / reproducing light source 21 made of, for example, a blue laser light source, and the laser light from the recording / reproducing light source 21 into signal light and reference light having different polarization directions. The first light separating means 22a made of a splitter and, for example, a part of the light for reference light and the other light for the first reference light Lr1 ′ and the second reference light by reflecting all of the light. A second light separation means 22b that divides the light Lr2 ′ into a first light, a signal light irradiation optical system that irradiates the surface of the recording medium 10 with the signal light Ls ′ as signal light Ls carrying data information, Is irradiated onto the surface of the recording medium 10 as the recording / reproducing reference light Lr1 having the same polarization direction as that of the signal light Ls, and the second reference light light Lr2 ′ is applied to the signal light Ls and the reference light Lr1 ′. Reference for recording and playback A spherical reference light irradiation optical system that irradiates the recording medium 10 as a verification reference light Lr2 having a polarization direction orthogonal to the light Lr1, and a reproduction light detection that detects reproduction light (diffracted light) from a hologram recorded on the recording medium 10. And an optical system.
A shutter 23, a polarizing plate 24, and a beam shaping lens 25 are disposed on the optical path of the laser light between the recording / reproducing light source 21 and the first light separating means 22a. Further, an ND filter 41 for adjusting the amount of the reference light is disposed on the optical path of the reference light between the first light separation unit 22a and the second light separation unit 22b. .

  The signal light irradiation optical system records a beam expander 31 that expands the beam diameter of signal light (for example, s-polarized light) Ls ′ from the first light separation means 22a, and signal light light Ls ′. The spatial light modulator (SLM) 32 which modulates using the spatial information corresponding to the page data to be output and emits light with the polarization direction (polarization plane) rotated by 90 °, and the light modulated by the spatial light modulator 32 ( For example, the Nyquist filter 34 for adjusting the frequency band on the Fourier plane of p-polarized light), the phase plate 35 for cutting unnecessary DC component light on the Fourier plane of the light from the Nyquist filter 34, and the phase plate 35 are transmitted. A signal light condensing objective lens 36 that condenses light as signal light Ls and irradiates the recording medium 10 is provided. 30 reflects the light Ls ′ for signal light incident through the beam expander 31 so as to be incident on the spatial light modulator (SLM) 32 and the light emitted from the spatial light modulator (SLM) 32. It is a polarizing prism beam splitter that transmits. Reference numeral 33 denotes a relay lens for causing the light modulated by the spatial light modulator 32 to enter the phase plate 35 via the Nyquist filter 34.

  The spherical reference light irradiation optical system reflects the half-wave plate 42 that changes the polarization direction of the second reference light beam Lr2 ′ and the first reference light beam (for example, p-polarized light beam) Lr1 ′. The polarization-selective mirror 45 that transmits the second reference light (for example, s-polarized light) Lr2 ″ whose polarization direction has been changed by the half-wave plate 42, the first reference light Lr1 ′, and the first reference light Lr1 ′ Each of the two reference light beams Lr2 ″ is converted into a spherical wave to be condensed as a recording / reproducing reference beam Lr1 and a verifying reference beam Lr2, and irradiated onto the recording medium 10 for reference light focusing objective lens 40. And. Reference numeral 44a in FIG. 2 denotes a reflection mirror that reflects the light Lr1 ′ for the first reference light separated by being reflected by the second light separation means 22b so as to enter the polarization selective mirror 45. Reference numeral 44b denotes a reflection mirror that reflects the light Lr2 'for the second reference light separated by passing through the second light separation means 22b and makes it incident on the polarization selective mirror 45 via the half-wave plate 42. is there. Reference numeral 44 c denotes a reflection mirror that reflects the first reference light beam Lr 1 ′ and the second reference light beam Lr 2 ″ to enter the reference light focusing objective lens 40.

  The reproduction light detection optical system transmits the reproduction light Lg1 having the same polarization direction as the recording / reproduction reference light Lr1 emitted from the hologram when the recorded hologram is irradiated with the recording / reproduction reference light Lr1. When the hologram is irradiated with the verifying reference light Lr2, the polarization separating means 50 that reflects the reproducing light Lg2 having the same polarization direction as that of the verifying reference light Lr2 emitted from the hologram and the reproducing light Lg1 are incident. The first imaging device 51a and the second imaging device 51b to which the reproduction light Lg2 is incident are provided. Reference numeral 52 denotes a reproduction light condensing lens that causes the reproduction light Lg1 and the reproduction light Lg2 to enter the polarization separation means 50.

  The recording medium driving mechanism includes a recording medium rotating mechanism that rotates (rotates) the recording medium 10 in a plane along the surface thereof, and a recording medium moving mechanism that moves the recording medium 10 in a plane along the surface thereof. It has. Further, as described above, when the so-called tilt shift multiplex recording is performed, the recording medium driving mechanism rotates the recording medium 10 so that the surface of the recording medium 10 is set with respect to the reference plane. The recording medium tilt mechanism for tilting is further provided.

In this hologram recording / reproducing apparatus, for example, laser light emitted from a recording / reproducing light source 21 composed of a blue laser light source is converted into signal light Ls ′ and reference light having different polarization directions by the first light separating means 22a. Divided into light for use.
The signal light Ls ′ is incident on the polarization prism beam splitter 30 via the beam expander 31, reflected by the polarization prism beam splitter 30, and applied to the spatial light modulator (SLM) 32. The spatial light modulator (SLM) 32 modulates the light Ls ′ for signal light with spatial information corresponding to the page data to be recorded, and the polarization direction (polarization plane) is rotated by 90 ° and emitted. . The light emitted from the spatial light modulator (SLM) 32 passes through the polarizing prism beam splitter 30 and is incident on the phase plate 35 via the Nyquist filter 34 by the relay lens 33. The signal light modulated by the spatial light modulator (SLM) 33 is adjusted in spatial frequency band by the Nyquist filter 34, and unnecessary DC component light on the Fourier plane is cut by the phase plate 35. The light transmitted through the phase plate 35 enters the signal light focusing objective lens 36, is condensed as signal light Ls, and is irradiated onto the surface of the recording medium 10.

  On the other hand, the light for reference light is incident on the second light separation means 22b via the ND filter 41, and the second light separation means 22b further supplies the first reference light light Lr1 ′ and the second light. Into the reference light beam Lr2 ′. The light Lr1 ′ for the first reference light is reflected by the reflection mirror 44a, enters the polarization selective mirror 45, and is reflected by the polarization selective mirror 45. The light Lr1 ′ for the first reference light reflected by the polarization selective mirror 45 is reflected by the reflection mirror 44c and enters the reference light collecting objective lens 40. The first reference light beam Lr1 ′ incident on the reference light focusing objective lens 40 is converted into a spherical wave and condensed as a recording / reproducing reference beam Lr1 having the same polarization direction as that of the signal light Ls. The surface of the recording medium 10 is irradiated. The second reference light beam Lr2 ′ is reflected by the reflecting mirror 44b and is incident on the half-wave plate 42. The light Lr2 ′ for the second reference light incident on the half-wave plate 42 is incident on the polarization selective mirror 45 with the polarization plane (polarization direction) rotated by 90 °. The light Lr2 ″ for the second reference light whose polarization direction has been changed passes through the polarization selective mirror 45 and travels along the same optical path as the light Lr1 ′ for the first reference light. The light is reflected by 44c and is incident on the reference light collecting objective lens 40. The second reference light light Lr2 ″ incident on the reference light condensing objective lens 40 is converted into a spherical wave and condensed as verification reference light Lr2 having a polarization direction orthogonal to the polarization direction of the signal light. Then, the surface of the recording medium 10 is irradiated. Here, the verifying reference light Lr2 is adjusted to a power (light quantity) smaller than the recording / reproducing reference light Lr1 by one or both of the half-wave plate 42 and the polarization selective mirror 45.

  Thereby, interference fringes due to the signal light Ls and the recording / reproducing reference light Lr1 having the same polarization direction are recorded on the recording medium 10 as a hologram, and the polarization direction of the signal light Ls and the polarization of the recording / reproducing reference light Lr1 are recorded. The verifying process is performed by simultaneously irradiating the recording medium 10 with the verifying reference light Lr2 having the polarization direction orthogonal to the direction. That is, when the hologram is properly recorded, the reproduction light Lg2 having the same polarization direction as that of the verifying reference light Lr2 is emitted from the recorded hologram, and this reproduction light Lg2 is reflected by the polarization separation means 50 and is reproduced. 2 is incident on the second image sensor 51b. Accordingly, it is confirmed that the hologram is recorded on the recording medium 10 by reproducing the information recorded on the hologram by the reproduction light Lg2 being incident on the second imaging element 51b. On the other hand, when it is confirmed that the hologram is not properly recorded (a writing error has occurred) due to the fact that the reproduction light from the hologram is not detected, for example, writing in the same location again or preparing separately Appropriate processing such as recording and reproduction is performed in the rewritten area.

In this hologram recording / reproducing apparatus, for example, multiple recording of holograms is performed by a slight distance shift in one direction (indicated by a white arrow in FIG. 1) along the surface of the recording medium 10 by a recording medium moving mechanism. This is done by repeatedly performing a new hologram recording process including a verify process in the (moved) state.
As described above, in the hologram recording / reproducing apparatus of the present invention, for example, the recording / reproducing area on the surface of the recording medium 10 is divided into a plurality of block units, and each block unit is used as a unit recording area to block spherical reference beam shift multiplex recording. Although it is performed for each unit, access to a unit recording area (book) in the recording medium 10 is performed by, for example, biaxial movement and rotation (rotation) of the recording medium 10.

  Further, when reproducing the data information relating to the hologram recorded on the recording medium 10, the reference light for recording / reproducing, in which the light amount of the reference light is adjusted by the ND filter 41 and the light amount is significantly reduced compared with the hologram recording time. Is irradiated onto the recording medium 10, the reproduction light Lg <b> 1 is emitted from the hologram recorded under the same reference light irradiation conditions as the recording / reproduction reference light. The reproduction light Lg1 from the hologram is emitted from the back side of the recording medium 10 and is incident on the polarization separation means 50 through the reproduction light condensing lens 52. The reproduction light Lg1 incident on the polarization separation means 50 is transmitted through the polarization separation means 50 and incident on the first image sensor 51a, whereby the data information recorded on the hologram is reproduced.

  Thus, in the hologram recording / reproducing apparatus, the verifying reference light Lr2 having the polarization direction orthogonal to the polarization direction of the signal light Ls and the polarization direction of the recording / reproducing reference light Lr1 is simultaneously irradiated during hologram recording. Thus, the verify process is performed. That is, the verify process is performed by immediately reproducing the hologram recorded on the recording medium 10. Therefore, according to the above-described hologram recording / reproducing apparatus, when a hologram writing error occurs, an appropriate process for the writing error can be quickly performed, so that the reliability of information recording can be improved, In addition, since it is not necessary to access the recorded information when performing the verify process, a series of information recording processes including the verify process can be speeded up. Further, the verification reference light Lr2 has a sufficiently smaller power (light quantity) than the recording / reproduction reference light Lr1, and therefore the verification reference light Lr2 has an extremely great influence on the recording of the hologram during recording of the hologram. Can be small.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, the hologram recording / reproducing apparatus is not limited to a configuration in which holograms are multiplexed and recorded by the spherical reference light shift multiplexing method, and the present invention is not limited to the holograms by the angle multiplexing recording method or the speckle reference light multiplexing recording method. This can also be applied to a configuration in which multiple recordings are recorded. Further, the recording medium may have any shape such as a disk shape or a card shape, and may be a transmissive type or a reflective type.

DESCRIPTION OF SYMBOLS 10 Recording medium 21 Recording / reproducing light source 22a 1st light separation means 22b 2nd light separation means 23 Shutter 24 Polarizing plate 25 Beam shaping lens 30 Polarizing prism beam splitter 31 Beam expander 32 Spatial light modulator (SLM)
33 Relay Lens 34 Nyquist Filter 35 Phase Plate 36 Signal Light Condensing Objective Lens 40 Reference Light Condensing Objective Lens 41 ND Filter 42 Half Wave Plate 44a Reflecting Mirror 44b Reflecting Mirror 44c Reflecting Mirror 45 Polarization Selective Mirror 50 Polarization Separating Means 51a First imaging element 51b Second imaging element 52 Reproducing light condensing lens Lg1 Reproducing light Lg2 Reproducing light Lr1 Recording / reproducing reference light Lr1 ′ First reference light Lr2 Verifying reference light Lr2 ′ Second Light for reference light Lr2 ″ Light for second reference light Ls Signal light Ls ′ Light for signal light

Claims (6)

A recording / reproducing light source, first light separating means for splitting light from the recording / reproducing light source into signal light and reference light having different polarization directions, and the reference light for the first reference light Second light separating means for dividing the light for signal and light for second reference light, a signal light irradiation optical system for irradiating the recording medium with signal light as signal light carrying data information, The recording medium is irradiated with the first reference light beam as the recording / reproducing reference light beam having the same polarization direction as the signal light, and the second reference light beam is verified in the polarization direction orthogonal to the polarization direction of the signal light. An optical mechanism including a reference light irradiation optical system for irradiating a recording medium as reference light for use, and a reproduction light detection optical system for detecting reproduction light from a hologram recorded on the recording medium,
By simultaneously irradiating the recording medium with the signal light, the recording / reproducing reference light, and the verifying reference light, interference fringes between the signal light and the recording / reproducing reference light are recorded as a hologram and A hologram recording / reproducing apparatus, wherein a verification process is performed by reproducing a recorded hologram with the reference light for verification.   2. The hologram recording / reproducing apparatus according to claim 1, wherein the power of the verifying reference light is smaller than the power of the recording / reproducing reference light. The recording / reproducing reference beam and the verifying reference beam are spherical waves,
A moving mechanism for moving one of the optical mechanism and the recording medium in one direction relative to the other along the surface of the recording medium;
3. The hologram recording / reproducing apparatus according to claim 1, wherein the hologram is multiplex-recorded on a recording medium by a shift multiplex recording method. The interference fringes between the signal light carrying the data information and the reference light are recorded as a hologram on the recording medium, and the data information recorded on the hologram is obtained by irradiating the reference light to the recording medium on which the hologram is recorded. In the hologram recording / reproducing method for reproducing,
Simultaneously irradiate the recording medium with signal light having a predetermined polarization direction, recording / reproducing reference light having the same polarization direction as the signal light, and verification reference light having a polarization direction orthogonal to the polarization direction of the signal light. The hologram recording is characterized in that the interference fringes between the signal light and the recording / reproducing reference light are recorded as a hologram, and the recorded hologram is reproduced by the verifying reference light to perform a verifying process. Playback method.   5. The hologram recording / reproducing method according to claim 4, wherein the verifying reference light is irradiated with a power smaller than that of the pre-recording / reproducing reference light. A spherical wave is used as a reference beam for recording and reproduction and a reference beam for verification.
6. The hologram recording / reproducing method according to claim 4, wherein the hologram is multiplexed and recorded by a shift multiplexing method.

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