CN114694692A - Multiplex recording and reproducing method, recording and reproducing apparatus - Google Patents
Multiplex recording and reproducing method, recording and reproducing apparatus Download PDFInfo
- Publication number
- CN114694692A CN114694692A CN202011612428.3A CN202011612428A CN114694692A CN 114694692 A CN114694692 A CN 114694692A CN 202011612428 A CN202011612428 A CN 202011612428A CN 114694692 A CN114694692 A CN 114694692A
- Authority
- CN
- China
- Prior art keywords
- reference light
- medium
- hologram
- recorded
- recording
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 78
- 238000000926 separation method Methods 0.000 claims description 2
- 238000006073 displacement reaction Methods 0.000 abstract description 2
- 239000013598 vector Substances 0.000 description 25
- 230000003287 optical effect Effects 0.000 description 16
- 238000010586 diagram Methods 0.000 description 8
- 230000010287 polarization Effects 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 3
- 238000007493 shaping process Methods 0.000 description 3
- 230000001902 propagating effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001093 holography Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
- G11B7/0065—Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
- G11B7/0045—Recording
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
- G11B7/005—Reproducing
Landscapes
- Holo Graphy (AREA)
Abstract
The invention provides a multiplex recording and reproducing method, a recording and reproducing apparatus, wherein the multiplex recording method includes: on the same track, holograms are recorded by multiplexing by linearly moving the storage medium and simultaneously changing the wavelengths of the signal light and the reference light at each shifted position. The reproduction method includes: the medium is linearly moved on the same track of the storage medium, reference light is made incident on the medium at the positions where the holograms are recorded, and any one of the holograms at the same position is reproduced at the position of each hologram by changing the incident angle of the reference light. The method combines two multiplexing recording methods of spherical reference light displacement multiplexing recording hologram and wavelength multiplexing recording hologram, the capacity of the hologram stored on the same track is increased by multiple times, and the storage capacity of the storage medium is improved; and the hologram recorded by wavelength multiplexing is reproduced at a high speed by continuously changing the incident angle of the reference light within a certain range, thereby realizing high-speed and high-efficiency reproduction of the hologram.
Description
Technical Field
The present invention relates to the field of optical holographic storage technology, and more particularly, to a multiplexing recording and reproducing method and a recording and reproducing apparatus.
Background
The optical holographic storage technology is to convert input information into a two-dimensional digital bitmap and load the bitmap into signal light, on a Fourier plane of the signal light, the modulated signal light and reference light interfere in a photopolymer medium to form a hologram, the hologram is stored in a storage medium refractive index change form, and the input information can be read by reproducing the hologram, so that the optical holographic storage technology is a common information recording and reproducing mode.
At present, the multiplexing methods for recording and reproducing mainly include (i) angular multiplexing recording, (ii) coaxial multiplexing recording, and (iii) spherical reference light shift multiplexing recording.
In the method (r), the hologram is multiplexed and recorded at the same position by changing the incident angle of the reference light. In this method, the bragg diffraction condition is satisfied only in a narrow angular range. For example, one hologram is recorded every time the incident angle of the reference light changes by about 0.1 °, so that several hundreds of holograms can be recorded at the same position. However, this method requires moving the medium to ensure that a new series of holograms is re-recorded at another location that does not overlap the previous hologram, with a large distance of movement (consistent with the hologram size) and limited storage capacity.
In the method two, the signal light is coaxial with the reference light, and the reference light is subjected to phase or amplitude speckle modulation. During recording of the holograms, it is possible to move each recorded hologram only a small distance relative to the previous hologram without having to ensure that the hologram at each position does not overlap with the holograms at other positions, for example by 2 μm or 3 μm in a two-dimensional plane. However, this method cannot use angular multiplexing recording and the storage capacity is still limited.
In method c, a new hologram can be recorded by moving the medium a distance using the spherical wave as a reference light. As shown in fig. 1, the signal light wave vector k is based on the bragg conditionsReference light wave vector krSum holographic grating direction vector kgA triangle is formed, when the medium is moved for a small distance after the hologram is recorded, the three vectors do not form the triangle any more, the Bragg condition is not established any more, the original recorded hologram cannot be reproduced, and then the next hologram can be recorded.
The reason for adopting the spherical reference light shift multiplexing recording is as follows: (1) in the angular multiplexing recording, different holograms are overlapped and recorded at the same position, the signal light or the reference light of the current hologram is scattered by the hologram recorded before, and meanwhile, the cross writing method also generates noise and reduces the signal-to-noise ratio; (2) in the coaxial holography method, since the signal light and the reference light are angularly close to each other, a large crosstalk is generated and a signal-to-noise ratio is lowered, so that signal quality is deteriorated.
For these two reasons, the spherical reference beam is used to avoid the influence of these noises, improve the diffraction efficiency, and further increase the multiplexing number of holographic recording.
Disclosure of Invention
The present invention is directed to overcoming at least one of the above-mentioned drawbacks of the prior art and providing a multiplexing recording and reproducing method and apparatus for solving the problem that the spherical reference light cannot improve the storage capacity by only shift multiplexing recording.
The technical scheme adopted by the invention comprises the following steps:
a multiplex recording method comprising: on the same track, holograms are recorded by multiplexing by linearly moving the storage medium and simultaneously changing the wavelengths of the signal light and the reference light at each shifted position.
The multiplexing recording method provided by the invention combines the shift multiplexing and the wavelength multiplexing of the spherical reference light to record the hologram, the capacity of the hologram stored on the same track is increased by multiple times, and the storage capacity of the storage medium is improved.
Further, the variation of each change of the wavelengths of the signal light and the reference light ranges from 0.3nm to 0.7 nm.
The wavelength variation of the signal light and the reference light for wavelength multiplexing needs to be controlled within a certain range, so that a certain wavelength difference is ensured when the reference light is used for multiplexing and recording different holograms, the situation of crosstalk between the recorded holograms cannot occur, and meanwhile, the wavelength difference also needs to be controlled within a set range, so that the number of holograms which can be recorded in a unit size of a medium can be optimized.
Further, on the same track, the distance of each movement of the medium ranges from 3 μm to 8 μm. Within this range, the moving distance of the medium needs to be large enough each time to ensure that mutual crosstalk between holograms does not occur during shift multiplexing; meanwhile, in order to make the number of holograms recordable in a unit size as large as possible, the medium moving distance needs to be as small as possible while ensuring no crosstalk.
Further, the pitch between different tracks of the medium ranges between 400 μm and 600 μm. As described in the background art, the difference in the distance of multiplexed recording between different tracks needs to be larger, and the pitch between different tracks needs to be maintained between 400 μm and 600 μm compared to the difference in the shift distance of the same track.
A reproduction method, comprising: linearly moving the medium on the same track of the storage medium, making reference light incident on the positions of the medium where the holograms are recorded, and reproducing any one of the holograms at the same position by changing the wavelength of the reference light at the position of each hologram; the holograms recorded by the medium are multiplexed and recorded by the above-described multiplexing recording method.
Since a plurality of holograms are recorded by shift multiplexing and wavelength multiplexing at the same shift position in the multiplex recording method, the holograms recorded by multiplex recording are reproduced by continuously changing the wavelength of the reference light within a certain wavelength range at each shift position of the medium during reproduction.
A reproduction method, comprising: linearly moving the medium on the same track of the storage medium, making reference light incident on the positions of the medium where the holograms are recorded, and reproducing any one hologram at the same position by changing the incidence angle of the reference light at the position of each hologram; the holograms recorded by the medium are multiplexed and recorded by the above-described multiplexing recording method.
Since a plurality of holograms are recorded by shift multiplexing and wavelength multiplexing at the same shift position in the multiplex recording method, and since the wavelength multiplexing recording is used in the multiplex recording, all holograms at the same shift position are generally reproduced by continuously changing the wavelength of the reference light within a certain range in the reproduction, but it is difficult to perform the continuous change at a fast speed within a certain range, and therefore, the present reproduction method is a preferable embodiment of the above reproduction method, in which the hologram recorded by wavelength multiplexing is reproduced by continuously changing the incident angle of the reference light within a certain range at the same shift position, and at the same time, it is relatively easy to perform the continuous change at a high speed within a certain range of the incident angle of the reference light, the present reconstruction method is therefore capable of reconstructing all holograms efficiently at high speed.
A recording device comprises a light source, a reference light path, a signal light path and a medium platform, wherein light emitted by the light source forms reference light transmitted along the reference light path and signal light transmitted along the signal light path after passing beams, the reference light and the signal light generate interference on a storage medium supported by the medium platform to form holographic storage image information, the medium platform further comprises a medium moving device, the device further comprises a wavelength adjusting device, the medium moving device is used for linearly moving the medium, and the wavelength adjusting device is used for changing the wavelengths of the reference light and the signal light at the same position so as to multiplex and record a hologram.
A reproducing apparatus includes a light source, a reference optical path, a reading device, and a medium stage, the light source forming a reference light transmitted along the reference optical path, and a reference light angle adjusting device; the media platform further comprises a media moving device; the medium moving device is used for linearly moving the storage medium supported by the medium platform to enable the reference light to be incident on the position of the medium where the hologram is recorded, and the reference light angle adjusting device is used for changing the incident angle of the reference light at the position of each hologram to enable the reference light to reproduce any one hologram on the same position of the medium; the reading device is used for reading the hologram reproduced by the reference light; the hologram recorded on the medium is multiplexed and recorded by the above-described recording apparatus.
A multiplex recording method comprising: recording a plurality of lines of holograms respectively using a plurality of wavelengths on the same track; holograms recorded in different wavelength multiplexes on the same track are reproduced at corresponding wavelengths when read, or holograms multiplexed at different wavelengths on the same track are reproduced by sequentially changing the incident angle of the reference light.
Further, the wavelength separation between the hologram lines multiplexed and recorded is 0.3nm to 0.7 nm.
Compared with the prior art, the invention has the beneficial effects that:
(1) the multiplexing recording method provided by the invention combines two multiplexing recording methods, namely the spherical reference light displacement multiplexing recording hologram and the wavelength multiplexing recording hologram, so that the capacity of the holograms stored on the same track is increased by multiple times, and the storage capacity is improved;
(2) the invention provides one of the alternative reproduction methods, which realizes the high-speed and high-efficiency reproduction of the hologram by reproducing the wavelength multiplexing recorded hologram at a higher speed in a certain range by continuously changing the incident angle of the reference light.
Drawings
Fig. 1 is a schematic diagram of the principle of shift multiplex recording.
Fig. 2 is a schematic diagram of the principle of cross-shift multiplexing recording.
Fig. 3 is a schematic diagram of shift distances required in shift multiplex recording.
Fig. 4 is a schematic diagram of the shift distance and the crosstalk area in the y direction.
Fig. 5 is a schematic view of the wavelength multiplexing principle in embodiment 1.
Fig. 6 is a schematic diagram of the principle and process of shift multiplexing and wavelength multiplexing in embodiment 1.
Fig. 7 is a schematic diagram of the principle of changing the incident angle of reference light for reproduction of a hologram recorded under reference light of a different wavelength in embodiment 1.
Fig. 8 is a schematic diagram illustrating the principle and process of changing the incident angle of the reference light for reproducing the hologram recorded under the reference light of different wavelengths.
Fig. 9 is a schematic view of the composition of the recording/reproducing apparatus in embodiment 1.
The figure includes: a laser 10; a shutter 20; a beam shaping prism group 30; a polarization beam splitter prism 40; a first polarization beam splitter prism 41; a second polarizing beam splitter prism 42; an attenuator 50; a half wave plate 60; a mirror 70; a first reflecting mirror 71; a second mirror 72; a third mirror 73; an acousto-optic modulator (AOM)80 or galvanometer 80; a relay lens group 90; a first relay lens group 91; a second relay lens group 92; a beam expanding collimator 100; a spatial light modulator 110; a Nyquist filter 120; a Fourier lens 130; a first Fourier lens 131; a second Fourier lens 132; a holographic disk 140; a camera 150.
Detailed Description
The drawings are only for purposes of illustration and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
Example 1
There are two methods for holographic recording using spherical reference beams, and a method (1) is referred to as a cross shift multiplex recording method in which shift multiplex recording is performed in a two-dimensional manner as shown in fig. 2 and then multiplex recording is performed in a form of crossing each other, so that the number of times of multiplex recording by the shift multiplex method is increased by several times, but as shown in fig. 2, the number of times of multiplex recording is inevitably limited to 8 times because a crossing angle is required to be 45 ° or more. Method (2) as shown in fig. 3, fig. 3 shows the requirement of the shift amount of the optical disc in each direction in the spherical reference light shift multiplexing method, and the bragg condition determines the moving direction and the moving distance of the shift multiplexing, so that a new hologram can be recorded by moving only 5 μm. However, in the direction perpendicular to x, a sufficiently large shift distance is required to ensure that the reproduction signal light and the crosstalk do not overlap, and as shown in fig. 3 and 4, a shift amount of 500 μm or more is required for the shift. Therefore, the storage capacity cannot be improved by the shift multiplexing alone.
Based on this, the present embodiment provides a multiplexing recording method, including:
on the same track of the storage medium, holograms are multiplexed by linearly moving the storage medium and simultaneously changing the wavelengths of the signal light and the reference light at each shifted position.
Specifically, the storage medium refers to a medium for recording hologram storage information, i.e., a hologram, formed after interference of the reference light and the signal light, and may be, for example, an optical disc. The tracks on the storage medium refer to a range of positions for multiplexed recording of holograms, the tracks being linearly distributed on the storage medium and not crossing each other. A mark for starting recording and a mark for ending recording of the hologram are generally provided on the track so that an initial recording position and an ending recording position of the track can be known through the marks at the time of multiplex recording or reproduction.
The specific process of the multiplexing recording method is as follows:
at least one hologram is recorded at a shift position of each storage medium by interference between signal light and reference light by linearly moving the storage medium, which is referred to as shift multiplexing recording in multiplexing recording holograms, in a direction of a track, and specifically, the distance of each movement of the storage medium ranges from 3 μm to 8 μm, ensuring that no crosstalk, preferably 5 μm, occurs between holograms recorded at different shift positions. The distance between different tracks on the storage medium is in the range of 400-600 μm, ensuring that the holograms between different tracks do not generate cross-talk, preferably 500 μm.
While recording a hologram at each shift position of the medium, recording more than one hologram at the same shift position by changing the wavelength of the signal light and the reference light, which belongs to the wavelength multiplexing recording in the multiplexing recording hologram, as shown in fig. 5, which is the principle of wavelength multiplexing, fig. 5 is drawn with an Ewald sphere (an Ewald diffraction sphere), whose k vector is composed of a signal light vector ks, a reference light vector kr, and a grating vector kg (hologram), and when three k vectors form a triangle, that is, a bragg condition is satisfied, the grating vector kg (hologram) is reproduced. According to this principle, if the wavelength is changed during recording, a corresponding plurality of holograms can be recorded at the same position, each of which will be reproduced by the reference light of the corresponding wavelength independently of each other.
Specifically, the change amount of each change of the wavelengths of the signal light and the reference light is the same, and the change amount of each change, namely the wavelength difference Δ λ, is at least 0.3nm, so that the holograms which are wavelength-multiplexed and recorded at the same shift position can not be in crosstalk. Preferably, since the wavelengths of the reference light and the signal light should be maintained within a certain range, the wavelength difference Δ λ is set to 0.7nm at most, so that the number of times the wavelengths of the reference light and the signal light are changeable within a certain wavelength range is not too small. On the basis of a linearly moving medium, at each shift position, a hologram formed by interference of reference light and signal light with an initial wavelength λ can be recorded first, and the number of times that the reference light and the signal light can be changed in a certain wavelength range is indirectly represented by sequentially changing the wavelengths of the signal light and the reference light to record a new hologram based on the aforementioned wavelength difference Δ λ: the number of holograms that can be recorded at the same shift position in addition to the holograms recorded by the reference light and the signal light of the initial wavelength λ; for example, if the number of times that the reference light and the signal light are variable in a certain wavelength range is 3 times, 4 different holograms can be multiplexed and recorded at the same shift position, and there is no crosstalk between the holograms, the number of holograms recorded in the medium increases by 3 times as compared with the number of holograms multiplexed and recorded by the shift-only method.
The multiplexing recording method provided by the embodiment records the holograms by combining shift multiplexing and wavelength multiplexing, so that the capacity of the holograms stored on the same track is increased by multiple times, and the storage capacity of the storage medium is improved. As shown in fig. 6, when the initial wavelength λ of the reference light and the initial wavelength λ of the signal light are 405nm, the wavelength range is 405nm to 407.5nm, and the wavelength difference Δ λ is 0.7nm, the wavelengths of the reference light and the signal light can be changed 3 times within the range. Taking the example of multiplexing and recording holograms with reference light and signal light on the track 1, first, the initial recording position of the track 1 is located by a mark where recording starts with the hologram of the track 1, the first hologram is recorded on the initial recording position of the track 1 by interference of the reference light and signal light with λ 405nm, the wavelengths of the reference light and signal light are changed to λ 1-405.7 nm, the second hologram is recorded on the position, the wavelengths of the reference light and signal light are changed to λ 2-406.4 nm, the third hologram is recorded on the position, the wavelengths of the reference light and signal light are changed to λ 3-407.1 nm, and the fourth hologram is recorded on the position; since the wavelengths of the reference light and the signal light cannot be changed any more in their wavelength ranges, the medium is linearly moved in the direction of the track 1 to a first shift position which is 5 μm away from the initial recording position, 4 holograms … … are multiplexed and recorded at the first shift position in the aforementioned wavelength multiplexing manner, and so on, after the storage medium is moved to the track 1 end recording position and the last multiplexing recording of the holograms has been completed, the storage medium is moved to the track 2, the distance Δ L between the track 2 and the track 1 is preferably 500 μm, the initial recording position of the track 2 is located by a mark where the recording of the hologram of the track 2 is started, and the above steps are repeated for the multiplexing recording of the holograms of the track 2 until all tracks of the medium have been recorded.
Based on the above multiplex recording method, the present embodiment also provides a reproduction method for reproducing any one of all holograms recorded by the above multiplex recording method.
The reproduction method comprises the following steps: the medium is linearly moved on the same track of the storage medium, reference light is made incident on the medium at the positions where the holograms are recorded, and any one of the holograms at the same position is reproduced at the position of each hologram by changing the wavelength of the reference light.
Specifically, the position of the medium where the hologram is recorded refers to each shift position at which the storage medium is linearly moved at the time of multiplex recording, and the reference light is made incident to each shift position by sequentially linearly moving the medium. Since the multiplexing recording method records a plurality of holograms by shift multiplexing and wavelength multiplexing at the same shift position, the holograms recorded by wavelength multiplexing at all the shift positions of the medium can be reproduced by continuously changing the wavelength of the reference light within a certain wavelength range at each shift position of the medium, and the principle can be explained with reference to fig. 5 and the principle corresponding to fig. 5, which is not repeated here.
However, the above-mentioned reconstruction method has a disadvantage that since the wavelength of the reference light needs to be continuously changed within a certain range during reconstruction, the continuous change of the wavelength of the reference light is difficult to be realized at a high speed, thereby affecting the reconstruction efficiency of the hologram.
Based on this, the present embodiment also provides a preferable reproduction method for reproducing also any one of all the holograms recorded by the above-described multiplex recording method.
The alternative reproduction method is: the medium is linearly moved on the same track of the storage medium, reference light is made incident on the medium at the positions where the holograms are recorded, and any one of the holograms at the same position is reproduced at the position of each hologram by changing the incident angle of the reference light.
Since a plurality of holograms multiplexed and recorded by the above-mentioned multiplexing recording method are multiplexed and recorded by another reproduction method, and since the multiplexing recording method records a plurality of holograms by shift multiplexing and wavelength multiplexing at the same shift position, when reproducing, the hologram should be first positioned on each shift position recorded on the storage medium, since the multiplexing recording is performed by wavelength multiplexing, when reproducing, all holograms at the same shift position are generally reproduced by continuously changing the wavelength of the reference light within a certain range, that is, the reproduction method provided by the previous method is used, but the above-mentioned disadvantages exist in the reproduction method, and therefore, the present reproduction method adopts the following scheme: in the same shift position, the incident angle of the reference light is continuously changed within a certain range to reproduce the hologram recorded in wavelength multiplexing, as shown in fig. 7, fig. 7 is a diagram of an Ewald sphere (an elvan diffraction sphere), a k vector of the Ewald sphere consists of a signal light vector ks, a reference light vector kr and a grating vector kg (hologram), if the grating vector kg (hologram) is obtained by using the signal light vector ks and the reference light vector kr during recording, the grating vector kg (hologram) can be reproduced by changing the incident angle of the reference light vector kr ', and the grating vector kg (hologram) is reproduced by using the reference light vector kr ' and the corresponding signal light vector ks ', and then the reference light vector kr ', the signal light vector ks ' and the grating vector kg form a triangle, so that the bragg condition is satisfied. According to this principle, at the time of hologram reproduction, it is possible to reproduce respective holograms recorded by interference of reference light and signal light of different wavelengths by continuously changing the incident angle of the reference light. Meanwhile, since it is relatively easy to realize to continuously change the incident angle of the reference light within a certain range at a high speed, the present reproducing method can efficiently reproduce any one of all holograms recorded by all the above-described multiplex recording methods.
Specifically, since the wavelength difference Δ λ preferably ranges from 0.3 to 0.7nm, when reproducing a hologram recorded by wavelength multiplexing by changing the incident angle of the reference light, the continuous change of the incident angle of the reference light requires a continuous change at a frequency of several tens MHz to be able to cope with the change accuracy of the wavelength, otherwise it is difficult to reproduce the hologram recorded by wavelength multiplexing by angle change.
As shown in fig. 8, when the initial wavelength λ of the reference light and the initial wavelength λ of the signal light are 405nm, the wavelength range is 405nm to 407.5nm, and the wavelength difference Δ λ is 0.7nm, the wavelengths of the reference light and the signal light can be changed 3 times (λ 1 is 405.7nm, λ 2 is 406.4nm, and λ 3 is 407.1nm, respectively) within the range, that is, the number of holograms multiplexed and recorded at each shift position of the medium is 4.
Taking the holograms recorded by multiplexing the reference light and the signal light on the track 1 as an example, the initial recording position of the track 1 is first located by a mark where the recording of the hologram of the track 1 is started, 4 ranges in which the incident angle of the reference light needs to be changed when the reference light and the signal light of λ, λ 1, λ 2 and λ 3 interfere with the recorded 4 holograms are determined, the incident angle of the reference light is changed in each range at a high speed, respectively, the hologram recorded when the incident angle of the reference light is changed to θ 1 is reproduced when the wavelength λ of the reference light and the wavelength of the signal light is 405nm, the hologram recorded when the wavelength of the reference light and the wavelength of the signal light is 406.4nm when the incident angle is changed to θ 2, the hologram recorded when the wavelength of the reference light and the wavelength λ 3 of the signal light is 407.1nm when the incident angle is changed to θ 3, and when the holograms at one position have all been reproduced, the linearly moving medium makes the reference light incident on the next position where the hologram is recorded, i.e., the first shifted position of the medium, the distance from the initial position is preferably 5 μm, and repeats the above-described operations, to reproduce the holograms recorded at different wavelengths by changing the incident angle of the reference light, and so on, and when the storage medium is moved to the end recording position of the track 1 and the reproduction of the last hologram has been completed, moves the storage medium to the track 2, the distance Δ L between the track 2 and the track 1 is preferably 500 μm, positions the position where the track 2 starts recording the hologram, and performs the hologram reproduction of the track 2 until all tracks of the medium have been reproduced.
Based on the above-mentioned multiplexing recording method and the above-mentioned preferred reproducing method, this embodiment further provides a recording apparatus including a light source, a reference optical path, a signal optical path, and a medium platform, where light emitted by the light source is split into reference light propagating along the reference optical path and signal light propagating along the signal optical path after splitting, the reference light and the signal light interfere with each other on a storage medium supported by the medium platform to form holographic storage image information, the medium platform further includes a medium moving device, the recording apparatus further includes a wavelength adjusting device, the medium moving device is configured to linearly move the medium, and the wavelength adjusting device is configured to change the wavelengths of the reference light and the signal light at the same position to multiplex and record a hologram.
Specifically, as shown in fig. 9, the overall structure of the recording apparatus is schematically illustrated, the light source is a laser 10, the laser 10 outputs a beam of light, the light passes through a shutter 20, a beam shaping prism set 30 and a polarization beam splitting prism 40 in sequence, and the light is split into the reference light path and the signal light path by a first polarization beam splitting prism 41. The signal light passes through the beam expanding collimator 100, is reflected to the spatial light modulator 110 by the second polarization beam splitter prism 42 to load a signal, passes through the second polarization beam splitter prism 42 again, sequentially passes through the second relay lens group 92, the third reflective mirror 73 and the first fourier lens 131, and reaches the holographic disk 140, and the holographic disk 140 is fixed on a medium platform. The reference light is reflected by the first reflecting mirror 71 after passing through the attenuator 50 and the half-wave plate 60 in sequence, then enters the Acoustic Optical Modulator (AOM)80 or the galvanometer to be subjected to angle modulation, and then reaches the holographic disk 140 after being subjected to beam expanding collimation by the collimating structure formed by the second reflecting mirror 72 and the first relay lens group 91. The reference light and the signal light interfere with each other on the holographic disk 140 supported by the medium platform, so as to form holographic storage image information, i.e. a hologram, the holographic disk 140 is the storage medium, the medium platform is further provided with a medium moving device for linearly moving the holographic disk 140, and the wavelength adjusting device is used for adjusting the wavelength of the light output by the laser 10.
The recording apparatus provided in this embodiment can be used to perform the above-mentioned multiplexing recording method, first, the medium moving means linearly moves the holographic disk 140 to a first track of the holographic disk 140, the initial recording position of the track is located by a mark where recording of a hologram is started, the reference light and the signal light with the initial wavelength λ reach the initial recording position of the first track of the holographic disk 140 by using the reference optical path and the signal optical path shown in fig. 9, the first hologram is recorded at the position after the interference between the reference light and the signal light, the wavelength adjusting means adjusts the wavelength of the light output from the laser 10 to λ 1 according to the wavelength difference Δ λ, thereby changing the wavelength of the reference light and the signal light to λ 1, the reference light and the signal light with the wavelength λ 1 record a second hologram at the same position along the original optical path, and the wavelength adjusting means continues to adjust the wavelength of the light output from the laser 10 n times according to the wavelength difference Δ λ (respectively denoted as λ 2, λ, b, c, λ 3 … … λ n) so that n holograms are recorded at the same position by the reference light and the signal light having wavelengths λ 2 and λ 3 … … λ n, respectively, a total of n +1 holograms are recorded at the same shift position. When the wavelengths of the reference light and the signal light cannot be changed any more in the wavelength range thereof, the medium moving device controls the medium to move linearly in the direction of the first track to a first shift position, the distance from the first shift position to the initial position is preferably 5 μm, n +1 holograms … … are multiplexed and recorded at the first shift position in the aforementioned wavelength multiplexing manner, and so on, when the storage medium is moved to the end recording position of the first track and the multiplexing recording of the last hologram has been completed, the medium moving device moves the storage medium to a second track, the distance Δ L between the second track and the first track is preferably 500 μm, the initial recording position of the second track is located, and the hologram multiplexing recording of the second track is performed until all tracks of the medium have been recorded.
Based on the above-described reproduction method, the present embodiment also provides a reproduction apparatus for reproducing any one of all the holograms recorded on the holographic disk 140 by the above-described recording apparatus. The reproducing apparatus includes a light source, a reference light path, a reading device, and a medium stage, the light source forming a reference light transmitted along the reference light path, and further includes a reference light angle adjusting device, and the medium stage further includes a medium moving device.
The medium moving device is used for linearly moving the storage medium supported by the medium platform to enable the reference light to be incident on the position where the hologram is recorded on the storage medium supported by the medium platform (namely each shift position of the medium during recording), and the reference light angle adjusting device is used for changing the incident angle of the reference light at the position of each hologram so as to enable the reference light to reproduce any one hologram at the same position; the reading device is used for reading the hologram reproduced by the reference light.
Specifically, the reproduction apparatus can also realize its function based on the configuration shown in fig. 9, in which the light source is a laser 10, and the laser 10 outputs one beam of light, which passes through a shutter 20, a beam shaping prism group 30, and a polarization beam splitting prism 40 in this order, and is split into two beams of light by a first polarization beam splitting prism 41, one of which is a reference beam. The reference light is reflected by the first reflecting mirror 71 after passing through the attenuator 50 and the half-wave plate 60 in sequence, then enters the Acoustic Optical Modulator (AOM)80 or the galvanometer to be subjected to angle modulation, and then reaches the holographic disk 140 after being subjected to beam expanding collimation by the collimating structure formed by the second reflecting mirror 72 and the first relay lens group 91. The reading device is a camera 150 in fig. 9, the reference light can reproduce a plurality of signal lights after being incident on the holographic disk 140, the signal lights are incident on the camera 150 after passing through the second fourier lens, and the camera 150 is the above-mentioned reading device for reading the reproduced signal lights to reproduce the hologram. Since the acousto-optic modulator (AOM)80 or the galvanometer is used to perform angle modulation on the reference light, in the structure shown in fig. 9, the acousto-optic modulator (AOM)80 or the galvanometer is the above-described reference light angle adjusting means.
Specifically, a beam splitter is further provided on the reference light path for splitting the reference light, and the holograms on the plurality of tracks of the medium can be reproduced by the plurality of reference lights, respectively.
The description will be given by taking as an example a hologram on a first track of one of the reference beams reproducing medium:
first, a medium moving means linearly moves a hologram disc 140 to a first track of the hologram disc 140, locates an initial recording position by a mark where recording of a hologram starts on the track, determines n +1 change ranges of an incident angle of reference light according to wavelength values λ, λ 1, λ 2, λ 3 … … λ n of the reference light and signal light when the recording means performs multiplex recording, and changes the incident angle of the reference light at a high speed using an acousto-optic modulator (AOM)80 or a galvanometer mirror in each change range, respectively, reproduces a hologram recorded when the incident angle of the reference light is changed to θ 1 and reproduces all holograms at one position by analogy with a hologram … … recorded when the incident angle is changed to θ 2 and the wavelength of the reference light is λ 1, when holograms at one position have been reproduced, the medium moving means linearly moves the medium so that the reference light is incident on the next position where the hologram is recorded, i.e., a first shifted position of the medium, which is preferably 5 μm apart from the initial position, and repeats the aforementioned operation using an acousto-optic modulator (AOM)80 or a galvanometer to reproduce the holograms recorded at different wavelengths by changing the incident angle of the reference light.
It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention claims should be included in the protection scope of the present invention claims.
Claims (10)
1. A multiplex recording method, comprising: holograms are multiplexed recorded by linearly moving the medium and simultaneously changing the wavelengths of the signal light and the reference light at each shifted position on the same track of the storage medium.
2. The multiplex recording method according to claim 1, wherein a variation amount per change of the wavelength of said signal light and said reference light ranges from 0.3nm to 0.7 nm.
3. The multiplex recording method of claim 2 wherein the distance of each movement of said medium on the same track is in the range of 3 μm to 8 μm.
4. The multiplex recording method of claim 3, wherein the pitch between different tracks of said medium is in the range of 400 μm to 600 μm.
5. A reproduction method, characterized by comprising: linearly moving the medium on the same track of the storage medium, making reference light incident on the positions of the medium where the holograms are recorded, and reproducing any one of the holograms at the same position by changing the wavelength of the reference light at the position of each hologram;
the hologram recorded in the medium is multiplex-recorded by the multiplex recording method according to any one of claims 1 to 4.
6. A reproduction method, characterized by comprising: linearly moving the medium on the same track of the storage medium, making reference light incident on the positions of the medium where the holograms are recorded, and reproducing any one hologram at the same position by changing the incident angle of the reference light at the position of each hologram;
the hologram recorded in the medium is multiplex-recorded by the multiplex recording method according to any one of claims 1 to 4.
7. A recording device comprises a light source, a reference light path, a signal light path and a medium platform, wherein light emitted by the light source forms reference light transmitted along the reference light path and signal light transmitted along the signal light path after passing beams, the reference light and the signal light generate interference on a storage medium supported by the medium platform to form holographic storage image information,
the medium stage further includes a medium moving device for linearly moving the medium, and the wavelength adjusting device is configured to change the wavelengths of the reference light and the signal light at the same position to multiplex-record the holograms.
8. A reproduction apparatus comprising a light source, a reference light path, reading means and a media platform, the light source forming reference light which is transmitted along the reference light path,
the device also comprises a reference light angle adjusting device; the media platform further comprises a media moving device;
the medium moving device is used for linearly moving the storage medium supported by the medium platform to enable the reference light to be incident on the position of the medium where the hologram is recorded, and the reference light angle adjusting device is used for changing the incident angle of the reference light at the position of each hologram to enable the reference light to reproduce any one hologram on the same position of the medium; the reading device is used for reading the hologram reproduced by the reference light;
the hologram recorded on the medium is multiplex recorded by the recording apparatus of claim 7.
9. A recording and reproducing method, comprising: recording a plurality of lines of holograms respectively using a plurality of wavelengths on the same track; holograms recorded in different wavelength multiplexes on the same track are reproduced at corresponding wavelengths when read, or holograms multiplexed at different wavelengths on the same track are reproduced by sequentially changing the incident angle of the reference light.
10. The recording and reproducing method according to claim 9, wherein the wavelength separation between the hologram lines multiplexed-recorded is 0.3nm to 0.7 nm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011612428.3A CN114694692A (en) | 2020-12-30 | 2020-12-30 | Multiplex recording and reproducing method, recording and reproducing apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011612428.3A CN114694692A (en) | 2020-12-30 | 2020-12-30 | Multiplex recording and reproducing method, recording and reproducing apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114694692A true CN114694692A (en) | 2022-07-01 |
Family
ID=82132169
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011612428.3A Pending CN114694692A (en) | 2020-12-30 | 2020-12-30 | Multiplex recording and reproducing method, recording and reproducing apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114694692A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1530774A (en) * | 2003-03-10 | 2004-09-22 | 英法塞技术公司 | Multi-location complex holography |
| KR20050099826A (en) * | 2004-04-12 | 2005-10-17 | 주식회사 대우일렉트로닉스 | Hdds worm system for using two laser beams different in wave length for recording/reproducing and method thereof |
| CN101206885A (en) * | 2006-12-15 | 2008-06-25 | 夏普株式会社 | Wavelength control method controlling the wavelength for recording or reproducing information with holography, hologram information processing apparatus and hologram recording medium |
| JP2008216573A (en) * | 2007-03-02 | 2008-09-18 | Funai Electric Co Ltd | Hologram recording device and hologram reproducing device |
| CN101276197A (en) * | 2007-03-27 | 2008-10-01 | 夏普株式会社 | Multiplexing hologram recording and reconstructing apparatus and method therefor |
| CN102737658A (en) * | 2011-03-31 | 2012-10-17 | 通用电气公司 | Multi-wavelength- holographic systems and methods |
| CN211879015U (en) * | 2020-01-23 | 2020-11-06 | 广东紫晶信息存储技术股份有限公司 | Holographic optical disk reading device and recording/reproducing device capable of high-speed parallel reproduction |
-
2020
- 2020-12-30 CN CN202011612428.3A patent/CN114694692A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1530774A (en) * | 2003-03-10 | 2004-09-22 | 英法塞技术公司 | Multi-location complex holography |
| KR20050099826A (en) * | 2004-04-12 | 2005-10-17 | 주식회사 대우일렉트로닉스 | Hdds worm system for using two laser beams different in wave length for recording/reproducing and method thereof |
| CN101206885A (en) * | 2006-12-15 | 2008-06-25 | 夏普株式会社 | Wavelength control method controlling the wavelength for recording or reproducing information with holography, hologram information processing apparatus and hologram recording medium |
| JP2008216573A (en) * | 2007-03-02 | 2008-09-18 | Funai Electric Co Ltd | Hologram recording device and hologram reproducing device |
| CN101276197A (en) * | 2007-03-27 | 2008-10-01 | 夏普株式会社 | Multiplexing hologram recording and reconstructing apparatus and method therefor |
| CN102737658A (en) * | 2011-03-31 | 2012-10-17 | 通用电气公司 | Multi-wavelength- holographic systems and methods |
| CN211879015U (en) * | 2020-01-23 | 2020-11-06 | 广东紫晶信息存储技术股份有限公司 | Holographic optical disk reading device and recording/reproducing device capable of high-speed parallel reproduction |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101002258B (en) | Optical head and multiplexing methods for reflection type holographic storage using spatial filtering | |
| JP5037391B2 (en) | Optical pickup, optical information recording / reproducing apparatus, and optical information recording / reproducing method | |
| US7843791B2 (en) | Optical information processing method and optical information reproducing method using multiplexing schemes capable of improving a density of recorded optical information | |
| JP7144553B2 (en) | Hologram disc reading method and apparatus capable of high-speed parallel reproduction | |
| WO2004034387A1 (en) | Information recording method, reproducing method and recording/reproducig method utilizing holography | |
| JP2009087448A (en) | Hologram recording and reproducing device and method | |
| JP5178411B2 (en) | Optical information recording / reproducing apparatus | |
| CN102290064B (en) | Reproduction apparatus and reproduction method | |
| JP5096191B2 (en) | Optical pickup, optical information reproducing apparatus and optical information recording / reproducing apparatus using the same | |
| CN211879015U (en) | Holographic optical disk reading device and recording/reproducing device capable of high-speed parallel reproduction | |
| JP2019053793A (en) | Hologram reproduction method and hologram reproduction device | |
| CN101714363B (en) | Information recording apparatus, information reproducing apparatus and recording media | |
| CN110992991A (en) | Holographic data storage device with single-arm structure | |
| CN114694692A (en) | Multiplex recording and reproducing method, recording and reproducing apparatus | |
| US20110317537A1 (en) | Multilayer coaxial holographic storage system | |
| CN101819804B (en) | Signal quality evaluating apparatus and method, and information recording medium | |
| KR100738978B1 (en) | Optical information reproducing apparatus using holography and optical information recording apparatus | |
| JP2009020134A (en) | Hologram element, hologram element fabricating apparatus, hologram element fabricating method and hologram reproducing apparatus | |
| CN111243628A (en) | Holographic storage device and method for simultaneous recording/reading on two sides | |
| JP6894110B2 (en) | Hologram recording / playback device | |
| JP5575391B2 (en) | Holographic recording medium and pickup for the recording medium | |
| JP6662521B2 (en) | Hologram recording / reproducing apparatus and hologram recording / reproducing method | |
| JP7144551B2 (en) | Reflective holographic optical storage method and apparatus | |
| CN211788163U (en) | Holographic storage device and storage medium based on angle-shift multiplexing | |
| JP2008533638A (en) | Method for recording data in a holographic data storage system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20220701 |