CN1734587A - Hologram recording apparatus and hologram recording method - Google Patents
Hologram recording apparatus and hologram recording method Download PDFInfo
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- CN1734587A CN1734587A CN 200510083252 CN200510083252A CN1734587A CN 1734587 A CN1734587 A CN 1734587A CN 200510083252 CN200510083252 CN 200510083252 CN 200510083252 A CN200510083252 A CN 200510083252A CN 1734587 A CN1734587 A CN 1734587A
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Abstract
At the time of varying the angle of a scan mirror for varying the angle of incidence of a reference beam on a hologram recording material, the angle of a slit is also varied in conjunction, whereby the beam diameter of the reference beam is varied by the slit so that the irradiation range on the hologram recording material will be constant without being varied according to the variation in the incidence angle of the reference beam. This ensures that the area of irradiation of the hologram recording material with the reference beam can always be kept constant, even when the incidence angle of the reference beam is varied at the time of recording holograms by the angle multiplex recording system.
Description
Technical field
The present invention relates to a kind of hologram recording apparatus and hologram recording method that on holographic recording medium, hologram is carried out multiplexed record by an angle multiplex system.
Background technology
In recent years, disclose by utilizing holographic technique to write down holographic recording/reproducing apparatus (seeing for example IBM J.RES DEVELOP VOL.44 NO.3, in May, 2000 " Hologrphic data storage (holographic data storage) ") with representation of large volumes of data.In holographic recording/reproducing apparatus, a kind of technology that is called multiplexed record is used for improving recording density.Unlike traditional record, the main points of this technology are an a large amount of individual page of position record.The representative example of multiplexed record comprises the multiplexed record of angle, the multiplexed record of displacement and the multiplexed record of phase code, and other the various systems such as spot is multiplexed also are known.
Figure 20 shows by the situation of angle multiplex system at the enterprising line item of hologram recording material (holographic recording medium).Be branched off into a signal beams and a reference beam from lasing light emitter (not shown) emitted laser, and in a light beam spatial modulator (not shown), stood spatial beam modulated signal light bundle 100 by a signal beams optical system (not shown), to be focused on the hologram recording material 10.On the other hand, reference beam 200 by a reference beam optical system (not shown) being incident on the scanning mirror 1, and by scanning mirror 1 reflection to be incident on the lens 2 in the reference beam optical system.Lens 2 and lens 3 constitute a 4f optical system, reference beam 200 passes lens 3 irradiation hologram recording materials 10 immediately, and the interference fringe that is produced by the interference between signal beams 100 and reference beam 200 is recorded on the hologram recording material 10.Here, when changing the angle of scanning mirror 1, change to change the incident angle of reference beam 200 on hologram recording material 10 according to angle, and based on each incident angle and different holograms by the multiplexed same posting field that is recorded on the hologram recording material 10.
Figure 21 shows that wherein the variation according to the incident angle of reference beam 200 changes the situation with the zone of reference beam 200 irradiation hologram recording materials 10.Because the diameter of light beam is constant and irrelevant with the difference of the incident angle (with respect to the normal of medium) of reference beam 200 on hologram recording material 10, so at the irradiated area under the situation of incident angle A less than the irradiated area under the situation of incident angle B, as from understanding the figure.
Figure 22 shows the variation pattern of the irradiated area of the incident angle variation that responds reference beam 200.Wherein the beam diameter of reference beam 200 is φ 1, when the incident angle that becomes big and reference beam 200 when the angle of scanning mirror 1 shown in Figure 10 A, 10B and 10C became big, the magnitude of press φ 1, φ 2 and φ 3 with the diameter of the part of reference beam 200 irradiation hologram recording materials 10 became greatly.
Reproduce in the register system in the angle multichannel, when changing the incident angle of reference beam 200 on hologram recording material 10, the same area part that signal beams 100 shines hologram recording material 10 with fixing incident angle, and irrelevant with the incident angle variation of reference beam 200.This means, when increasing the area that shines with reference beam 200, widen scope, comprise scope with signal beams 100 irradiations with reference beam 200 irradiation hologram recording materials 10.Yet, in essence, wish that reference beam 200 is radiated in such scope, thereby the scope with signal beams 100 irradiation hologram recording materials 10 covered the minimum degree of requirement.This is because the irradiation meeting of 200 pairs of unnecessary part of reference beam sensitization hologram recording material 10 excessively, brings the waste of its dynamic range and causes the reduction of recording capacity.
Summary of the invention
Thereby, a kind of hologram recording apparatus and a kind of hologram recording method need be provided, by this equipment and this method, by an angle multiplex system recorded hologram time, area total energy with reference beam irradiation hologram recording material keeps constant, even also be like this when changing the incident angle of reference beam.
Respond above-mentioned needs, according to one embodiment of present invention, provide a kind of pass through an angle multiplex system at record on the holographic recording medium by at the hologram recording apparatus of a signal beams with an interference fringe that interference produced between the reference beam that the incident angle on the holographic recording medium changes, wherein in a reference beam optical system, provide to be used for making the substantially invariable range of exposures fixed part of scope that shines holographic recording medium with holographic beam.
In the present invention, the range of exposures fixed part can be that a beam diameter that is used for regulating the beam diameter of reference beam is regulated part, and this beam diameter is regulated part and be can be provided in the reference beam optical system.
In addition, in the present invention, the range of exposures fixed part can comprise: diaphragm, and it is arranged regularly; A lens combination with the telecentric imaging optical system is used for shining this diaphragm with reference beam, and the optical routing of reference beam is used for changing a scanning mirror change of incident angle.
Thereby, according to one embodiment of present invention, for example by changing reference beam by the angle multiplex system and under the situation of multiplexed record data pattern at the incident angle on the holographic recording medium, can be according to the variation of the incident angle of incident beam, regulate the beam diameter of incident beam, and so regulate the beam diameter of reference beam, thereby offset the increase of increase reference beam diameter on the main axis direction on the holographic recording medium of the incident angle of following reference beam, feasible thus area substantially constant with reference beam irradiation holographic recording medium, and irrelevant with the incident angle variation of reference beam.This makes might prevent holographic recording medium by overexposure, with the recording capacity that keeps its dynamic range and guarantee to stipulate.
In addition, can provide: diaphragm, it is arranged regularly; Lens combination with the telecentric imaging optical system, be used for shining this diaphragm with reference beam, the optical routing of this reference beam is used for changing the scanning mirror change of incident angle, and by using the lens combination of having shone the telecentric imaging optical system of the holographic recording medium that is arranged to tilt with respect to optical axis by the reference beam of diaphragm, position relation between holographic recording medium and diaphragm can so be provided with, and makes holographic recording medium and diaphragm satisfy the Shcheimpflug rule.This structure guarantees to make with the area substantially constant of reference beam irradiation holographic recording medium irrelevant with the incident angle variation of reference beam, and can obtain and above identical effect.
In addition, a diffraction grating for example can be used as a diffractive optical device, and diffraction grating and holographic recording medium can arrange with imaging relations, makes a telecentric optical system (for example 4f optical system) between it.This structure guarantees, even since when the deflection angle of reference beam by the diffraction grating change when changing the incident angle on holographic recording medium thus, diffractive optical device and holographic recording medium also are in imaging relations, so can prevent to change the area with reference beam irradiation holographic recording medium.Moreover this effect can realize by only using one group of telecentric optical system, and can realize without any mechanical wear and other places, thereby might handle high sweep velocity and reduce the size and the weight of benchmark optical system.
According to the present invention, when changing the incident angle of reference beam on holographic recording medium by the angle multiplex system and carry out the multiplexed record of data pattern, by regulate the beam diameter of reference beam according to the variation of the incident angle of reference beam, so that offset the increase of increase reference beam diameter on the main axis direction on the holographic recording medium of the incident angle of following reference beam; Perhaps utilize with the lens combination of shining the telecentric imaging optical system of the holographic recording medium that is arranged to tilt with respect to optical axis, thereby satisfy the Shcheimpflug rule by position relation holographic recording medium and the diaphragm that is arranged between holographic recording medium and the diaphragm by the reference beam of diaphragm; Perhaps by arranging that with imaging relations diffraction grating and holographic recording medium make a telecentric optical system (for example 4f optical system) between it, and during recorded hologram based on the multiplexed register system of angle, can remain constantly with the area of reference beam irradiation holographic recording medium, and change irrelevant with the incident angle of reference beam.Therefore, even owing to when changing the incident angle of reference beam, do not change the reference beam irradiation area on the hologram plane, so reference beam can cover the Minimum Area that requires that comprises the signal beams zone all the time yet; As a result, possible: elimination is wasted regional exposure, eliminates the waste of the dynamic range of holographic recording medium, is reached the recording capacity that assurance is stipulated.
Description of drawings
Figure 1A and 1B are calcspars, and expression is according to a reference beam optical system of a kind of hologram recording apparatus of first embodiment of the invention.
Fig. 2 shows the variation that is incident on range of exposures under the situation on the plane surface at a light beam at a certain angle.
Fig. 3 A and 3B show the effect of the diaphragm of the beam diameter that is used for dwindling light beam.
Fig. 4 shows that the diaphragm of representing has the mode that obtains a normal under the situation of a thickness in Fig. 1.
Fig. 5 is a calcspar, and expression is according to a reference beam optical system of a kind of hologram recording apparatus of second embodiment of the invention.
Fig. 6 A, 6B and 6C are calcspars, and expression is according to a reference beam optical system of a kind of hologram recording apparatus of third embodiment of the invention.
Fig. 7 is a calcspar, and expression is according to another example of the reference beam optical system of the hologram recording apparatus of the 3rd embodiment.
Fig. 8 A, 8B and 8C are calcspars, and expression is according to the structure of a reference beam optical system of a kind of hologram recording apparatus of fourth embodiment of the invention.
Fig. 9 shows the operation as a kind of diffraction grating of the diffractive optical device of representing in Fig. 8.
Figure 10 A and 10B are illustrated in a kind of configuration example and the relation between scanner angle and deflection angle of the diffraction grating among Fig. 8.
Figure 11 is a calcspar, is illustrated in the operation of the reference beam optical system of representing among Fig. 8.
Figure 12 A and 12B are illustrated in the another kind of configuration example and the relation between scanner angle and deflection angle of the diffraction grating among Fig. 8.
Figure 13 shows the structure of the diffraction grating of issuable fault under the situation that is used for eliminating the diffraction grating of representing in using Figure 12.
Figure 14 represents the structure according to a benchmark optical system of a kind of hologram recording apparatus of fifth embodiment of the invention.
Figure 15 shows with the scope of the reference beam irradiation diffraction grating mode by the mask restriction of representing among Figure 14.
Figure 16 represents another example according to the hologram recording apparatus of the 5th embodiment that represents among Figure 14.
Figure 17 is a calcspar, and expression is according to the structure of a reference beam optical system of a kind of hologram recording apparatus of sixth embodiment of the invention.
Figure 18 A and 18B represent another example according to the reference beam optical system of the 6th embodiment that represents among Figure 17.
Figure 19 represents another example according to the reference beam optical system of the 6th embodiment that represents among Figure 17.
Figure 20 represents with cause angle multiplex system the correlation technique of a kind of reference beam optical system of hologram record on hologram recording material to be constructed.
Figure 21 shows the variation of shining the area of hologram recording material according to the variation of the incident angle of the reference beam of representing among Figure 20 with reference beam.
Figure 22 A, 22B and 22C represent with Figure 21 in the variation of incident angle of the reference beam represented change the mode of irradiated area relatively.
Embodiment
[example 1]
Figure 1A and 1B are calcspars, and expression is according to a reference beam optical system of a kind of hologram recording apparatus of first embodiment of the invention.The reference beam optical system of hologram recording apparatus has a diaphragm 11, scanning mirror 12, and the lens 13 and 14 of 4f optical system, and shines a kind of hologram recording material 15 with a reference beam 200.
Secondly, will the operation of this embodiment be described.In Figure 1A, reference beam 200 is by diaphragm 11, its incipient beam of light diameter phi 1 is adjusted to beam diameter φ ' thus, reference beam 200 is reflected with on the lens 13 and 14 that are incident on the 4f optical system by scanning mirror 12 then, and the lens 13 and 14 by the 4f optical system are handled, to shine hologram recording material 15 immediately.In this example, owing to will describe below, the diameter of the range of exposures of hologram recording material 15 is φ.
Generally, as shown in Figure 2, a parallel beam 38 with φ ' diameter is incident on occasion on the plane surface with respect to the normal of plane surface with angle θ, and the length of minor axis (with the perpendicular direction of the paper among Fig. 2) is constant, but the length φ of main shaft is " by following expression
φ″＝φ′/cosθ ...(1)
Therefore, when the incident angle of reference beam 200 changed, the reference beam area on hologram recording material changed.In order to address this problem, diaphragm 11 in this embodiment is inserted into.
Basically, by the incident reference beam being arranged to according to the incident angle of reference beam on medium
φ′＝φcosθ ...(2)，
Can offset variation owing to the reference beam area of incident angle difference.When in this φ ' substitution formula (1) time, see that the beam diameter on medium is φ, this equals the incipient beam of light diameter.
Here, general, the aperture arrangement of representing in as Fig. 3 A with diameter phi becomes the occasion that tilts with angle θ as shown in Fig. 3 B, and the radius of projection is rectangular projection φ cos θ on the direction of the angle of inclination.This equals above formula (2), thereby when the diaphragm 11 that is arranged in scanning mirror 12 fronts is arranged to the angle of an incident angle θ who equals reference beam 200, the beam diameter of reference beam 200 can narrow down to φ cos θ by diaphragm 11, and when making reference beam 200 be incident on the hologram recording material 15, the length of the main shaft of the range of exposures on recording materials 15 can be always φ.
The angle that Figure 1B is illustrated in the scanning mirror of representing among Figure 1A 12 is changed the situation that changes the incident angle of reference beam 200 on hologram recording material 15 thus.In this case, by also the angle of diaphragm 11 being changed the beam diameter that identical amount is dwindled reference beam 200 thus, the length of the main shaft of the range of exposures on hologram recording material 15 is φ all the time.
According to this embodiment, by dwindle the beam diameter of reference beam 200 according to the irradiating angle of reference beam 200 on hologram recording material 15 by diaphragm 11, length with the main shaft of the scope of reference beam 200 irradiation hologram recording materials 15 can remain constant, and irradiated area can remain under the minimum value of requirement consistently, and irrelevant with the incident angle of reference beam 200.Therefore, the waste of the dynamic range of hologram recording material 15 can be eliminated, and the recording capacity of regulation can be kept.
Although in this embodiment for simplicity, the thickness of supposing hologram recording material 15 is insignificant, is described, and the hologram recording material 15 of Shi Yonging is thick medium under multiple situation in practice.In these cases, always overlapping in order to guarantee in Fig. 4 by the part of 48 indications, this part is considered to dielectric surface, and calculating angle, the normal of in aforementioned calculation, its normal being used as simultaneously medium, can obtain thus and above identical result, and can remain on consistently under the minimum value of requirement with the area of reference beam 200 irradiation hologram recording materials 15, and irrelevant with the incident angle of reference beam 200.
[example 2]
Fig. 5 is a calcspar, and expression is according to a reference beam optical system of a kind of hologram recording apparatus of second embodiment of the invention.Here, in the following description, with those identical parts among first embodiment that in Figure 1A and 1B, represents by with the identical symbol indication of above use.Hologram recording apparatus in this embodiment has a kind of like this structure, wherein utilizes a changeable type ND optical filtering 21 that the intensity of reference beam 200 on hologram recording material 15 is kept constant, and other structure is identical with in first embodiment those.
Changeable type ND optical filtering 21 is inserted on the light path of reference beam 200 upstream side at diaphragm 11.Reference beam 200 is before inciding on the diaphragm 11, and intensity is by 21 decay of ND optical filtering.Degree by 21 decay of ND optical filtering changes according to the incident angle of reference beam 200 on hologram recording material 15.In particular, when the incident angle of reference beam 200 on hologram recording material 15 increases, reduce degree by 21 decay of ND optical filtering, so that keep the intensity of reference beam 200 on hologram recording material 15 constant, and keep the ratio of the intensity of the intensity of reference beam 200 and signal beams thus, whereby can be stably and carry out multiplexed recoding/reproduction in the angle multiplex system with constant-quality.
[example 3]
Fig. 6 A, 6B and 6C are calcspars, and expression is according to a reference beam optical system of a kind of hologram recording apparatus of third embodiment of the invention.Here, in the following description, with those identical parts among first embodiment that in Figure 1A and 1B, represents by with the identical symbol indication of above use.The reference beam optical system of hologram recording apparatus has the lens 16 of a catoptron 19, scanning mirror 12,4f optical system and 17, diaphragms 11, and the lens 13 and 14 of 4f optical system, and reference beam 200 incides on the holographic recording medium 15.Here should be noted that diaphragm 11 and hologram recording material 15 with a kind of like this position relation layout, make and satisfy " Shcheimpflug rule ".
Secondly, will the operation of this embodiment be described.In Fig. 6 A, reference beam 200 is incident on after its optical routing catoptron 19 changes on the scanning mirror 12 and by scanning mirror 12 reflections, and by the lens 16 and 17 of 4f optical system, so that be incident on the diaphragm opening portion of diaphragm 11 with 0 ° incident angle.Diaphragm diameter at diaphragm 11 is the occasion of φ, the beam diameter of the reference beam 200 by diaphragm 11 is φ, reference beam 200 with this beam diameter is incident on the lens 13 of 4f optical system, and the lens 14 by the 4f optical system are handled, so that immediately with 0 ° incident angle irradiation hologram recording material 15.
In this case, the angle of scanning mirror 12 changes in three kinds of modes representing in Fig. 6 A to 6C He will describe below.In the example of Fig. 6 A, lens 16 and 17 constitute a so-called 4f optical system, and lens 13 and 14 constitute another 4f optical system, and scanning mirror 12 and diaphragm 11 are in imaging relations, and diaphragm 11 and hologram recording material 15 also are in imaging relations.
In addition, although hologram recording material 15 is arranged to respect to inclined light shaft, but supposition hologram recording material 15 and diaphragm 11 are provided with a kind of like this position relation, make scioptics 13 and 14 satisfy the Shcheimpflug rule, thereby the diaphragm planar imaging are on hologram recording material 15.In addition, suppose that the reference beam 200 that shines the diaphragm plane immediately makes its irradiated area on diaphragm change according to the angle of scanning mirror 12, but reference beam 200 has a kind of like this beam diameter, make to cover the diaphragm plane and irrelevant with angle.Be in the occasion of imaging relations at diaphragm 11 with the scope of reference beam 200 irradiation hologram recording materials 15, the diameter phi of diaphragm 11 must be the diameter of range of exposures, thereby the diameter of range of exposures also be steady state value φ, and has nothing to do with the angle of scanning mirror 12; In addition, see that the reference beam 200 by diaphragm 11 is radiated on the same area of hologram recording material 15 immediately, and irrelevant with the angle of scanning mirror 12.
Fig. 6 B and 6C represent the reformed situation of the angle of scanning mirror 12, and on the basis of the above, the full diameter that shines the scope of hologram recording materials 15 with reference beam 200 is in steady state value φ.
According to this embodiment, the lens 16 and 17 of 4f optical system are inserted between scanning mirror 12 and the diaphragm 11, and pass through the lens 16 and 17 of 4f optical system by the reference beam 200 of scanning mirror 12 reflections, so that shine the diaphragm part of diaphragm 11 immediately, whereby, even diaphragm 11 is fixed with respect to the rotation of scanning mirror 12, also can realize dwindling the beam diameter of reference beam 200 by means of fixing diaphragm 11, and obtain and identical effect in first implements according to the incident angle variation of reference beam 200 on hologram recording material 15.Particularly, because diaphragm 11 can be maintained fixed with respect to the rotation of scanning mirror 12, so reduced mechanical instability and precision degenerates and similar fault, the reliability of equipment strengthens thus.
Explanation in passing, although use the 4f optical system in this embodiment, each 4f optical system is a kind of telecentric imaging optical system, and in general, can obtain identical effect when using a telecentric imaging optical system.
In addition, can adopt a kind of structure, in this structure, as shown in Figure 7, ND optical filtering 21 is inserted in the reference beam optical system upstream side at a scanning mirror 12, and when the incident angle of reference beam 200 on hologram recording material 15 increases, reduce degree by 21 decay of ND optical filtering, so that keep the intensity of reference beam 200 on hologram recording material 15 constant, make the reference beam 200 and the intensity rate of signal beams keep constant whereby, and can be stably and carry out multiplexed recoding/reproduction in the angle multiplex system with constant-quality.
[example 4]
Fig. 8 A to 8C is a calcspar, and expression is according to the structure of a reference beam optical system of a kind of hologram recording apparatus of fourth embodiment of the invention.Have 11, lens of a diffractive optical device (holography scanner) 12, lens 13, and a kind of hologram recording material 14 based on the reference beam optical system of the hologram recording apparatus of angle multiplex system.Diffractive optical device 11 plays an angular deflection device, to change the incident angle of reference beam 200 on hologram recording material 14.In addition, it is a kind of 4f optical system of telecentric imaging optical system that lens 12 and 13 constitute one, and diffraction grating 111 and hologram recording material 14 are arranged with mutual imaging relations.Compare with having the example 1 that is used for changing according to the angle of reference beam 200 mechanism of mechanical alteration aperture stop size, this structure makes might improve sweep velocity, so that prevent the mechanical mechanism wearing and tearing and increase the service life.In addition, because two 4f projection optical systems that are connected in series need a large amount of opticses and big space, so compare with the example 3 that two 4f projection optical systems that wherein are connected in series are inserted in the reference beam optical system, provide the convenient part of this method of diffraction grating to be, therefore the size of reference beam optical system and weight have also reduced the size and the weight of adapter.
Fig. 9 is illustrated in a detailed construction example of the diffractive optical device of representing among Fig. 8 A to 8C.The figure shows an example that uses a diffraction grating 111, diffraction grating 111 is the simplest as diffractive optical device 11.Incident beam is by diffraction grating 111 diffraction, and its angle is deflected.
Secondly, will the operation of this embodiment be described.In Fig. 8 A, reference beam 200 is incident on the diffraction grating 111, reference beam 200 is deflected according to diffraction grating 111 scanner angle a at this moment, be incident on the lens 12, and further handle by lens 13, so that be incident on the hologram recording material 14 with a angle according to scanner angle a.Similarly, as shown in Fig. 8 B, reference beam 200 is deflected according to the scanner angle b of diffraction grating 111, is incident on the lens 12, and is handled by lens 13, so that be incident on the hologram recording material 14 with an angle according to scanner angle b.Similarly, as shown in Fig. 8 C, reference beam 200 is deflected according to the scanner angle c of diffraction grating 111, is incident on the lens 12, and is handled by lens 13, so that be incident on the hologram recording material 14 with an angle according to scanner angle c.
Because the reference beam 200 that comes out from diffraction grating 111 forms image by the telecentric imaging optical system of representing at hologram recording material 14 among Figure 11, described its incident area (spot size of reference beam) on hologram recording material 14 is identical with the scope of said reference light beam.Because the scanner angle that the reference beam scope is independent of diffraction grating 111 is constant, so the scanner angle (being the incident angle of reference beam 200 on hologram recording material 14) that also is independent of diffraction grating 111 in the scope of formation image on the hologram recording material 14 with reference beam 200 irradiation hologram recording materials 14 also is constant.
Here, when in a kind of continuous change type beam flying shown in Figure 10 A and the 10B when the diffraction grating 111, the time period of light beam under certain angle is extremely short.As a result, extremely short by the recovery time of a holographic pages of angle multiplex system record.If the recovery time of a holographic pages is very short, under the lower situation of the diffraction efficiency of holographic data then more weak or record at the power of reproduction laser light, a little less than the light intensity that is received by imageing sensor became, S/N degenerates and reproduces than (signal to noise ratio (S/N ratio)) was impossible.When beam flying speed raises gradually so that when improving message transmission rate, these problems become more obvious.
Figure 12 A and 12B represent to be used for eliminating the structure of a kind of diffraction grating 121 of issuable fault under the situation of stating diffraction grating 111 in the use.Diffraction grating 121 has a kind of structure, and in this structure, the diffraction grating gap cuts apart the angle [alpha] interruption based on each and stepping ground changes, rather than changes continuously, as shown in Figure 12 A.In particular, the diffraction grating gap is constant in cutting apart angle [alpha], but the diffraction grating gap is cut apart angle [alpha] based on each and changed with predetermined ratio.Thereby, when using this diffraction grating 121, as shown in Figure 12B, deflection angle keeps constant in the scanner angle during the period of necessarily cutting apart in the angular range, but deflection angle enter next when cutting apart angle stepping ground change, and repeat this operation.In a word, as shown in Figure 15 B, can obtain a kind of variation of deflection angle responding scanning device angle and the relation of Discrete Change.In this case, the time that the incident angle of reference beam 200 is in certain angle becomes longer, and the reconstruction of hologram time become longer, thereby can obtain having the reproduced image of good S/N, and therefore, can improve message transmission rate.
According to this embodiment, by (in this example with diffractive optical device 11, diffraction grating 121) a galvanic reflex mirror (galvano mirror) of the light-beam scanner of replacement through being commonly used for the angle multiplex system, the interruption that can easily realize the incident angle of the reference beam shown in Figure 12 B changes, and even light intensity lower in the diffraction efficiency of holographic data, that received by imageing sensor is weak, and the situation of further rising message transmission rate under, also can obtain having the reproduced image of good S/N.
In addition, by utilizing the 4f optical system of forming by lens 12 and 13 diffraction grating 121 and hologram recording material 14 are arranged with mutual imaging relations, it is constant that irradiated area on hologram recording material 14 can keep, and change irrelevant with the incident angle of reference beam 200 on hologram recording material 14, can be set to exposed portion the minimum value of requirement whereby, and can prevent that the dynamic range of hologram recording material 14 from reducing.Moreover, because by the feasible constant area of one group of 4f optical system with reference beam 200 irradiation hologram recording materials 14, so can reduce the size and the weight of optical system, and since system without any the mechanical wear part, so system is good at aspects such as durabilities.
In addition, utilize the diffraction grating 111 of constructing shown in Figure 10 also can realize the mechanism that is used for the deflection angle step change shown in Figure 12 B.In this case, the substrate 112 that stepping ground rotates diffraction grating is just enough and need not rotate it continuously, but this method is being had any problem aspect the control rotating.
Explanation in passing is interrupted in the type that changes at deflection angle shown in Figure 12 A and the 12B, and it is constant distributing to each diffraction grating gap of cutting apart angle; Therefore, if with the incident angle of the corresponding reference beam 200 in diffraction grating gap on hologram recording material 14 in have deviation, the image of Zai Xianing thereby can be darker then.In view of this, distributing to the diffraction grating gap of cutting apart angle can be provided with very for a short time, even have some deviation in optimal incident angle in fact whereby, at this reproduced image that also can obtain becoming clear in the scope of angle of cutting apart owing to reference beams such as temperature variation 200.Figure 13 shows the variation that changes with the scanner angle in the situation deflect angle of using such diffraction grating, wherein the variation of angular range stepping ground is cut apart based on each in the diffraction grating gap, and the diffraction grating gap changes very little in cutting apart angular range.
Simultaneously, in the angle multiplex system, importantly, make the light intensity ratio between signal beams and reference beam constant.In this embodiment, although light intensity is very little with the variation of the beam area variation of reference beam 200, but light intensity ratio is owing to reflection or other reason that the reference beam incident angle depends in the surface of hologram recording material still changes, and therefore, wishes to compensate this trend.For this purpose, the diffraction efficiency of diffraction grating 111 (or 121) can change based on each deflection angle.Here, the diffraction efficiency section, the ratio between 0 rank light beam and 1 rank light beam is illustrated among Fig. 9.Might change diffraction efficiency by changing this ratio.There are some to be used for changing the known method of diffraction efficiency.
For example, are occasions of phase type at diffraction grating 111, can adopt a kind of method of regulating the phase changing capacity of diffraction grating 111.For example, can change diffraction efficiency by the thickness that changes the uneven part that forms diffraction grating, and cut apart the thickness that angular range changes the uneven part that constitutes diffraction grating based on each of diffraction grating 111, thereby the light intensity ratio between signal beams and reference beam is constant.
At diffraction grating 111 are occasions of amplitude type, utilization is cut apart the different coating of angular range absorptivity based on each of diffraction grating 111 so that change optical density, can change diffraction efficiency based on deflection angle, can make the light intensity ratio between signal beams and reference beam constant whereby.And the width of the diffraction grating by regulate forming diffraction grating 111 also might change diffraction efficiency, and utilize this point so that change light transmission, can make the light intensity ratio between signal beams and reference beam constant.
In this embodiment, undertaken by the angle multiplex system under 100 multiplexed situations, the diffraction grating gap of diffraction grating 111 is so cut, and realizes 100 multiplexed reference beam deflection angles thereby obtain being used for changeing by one.Yet, can adopt a kind of structure, in this structure, the diffraction grating gap is so cut, thereby by half way around realize 100 times multiplexed.
[example 5]
Figure 14 is a calcspar, and expression is according to the structure of a reference beam optical system of a kind of hologram recording apparatus of fifth embodiment of the invention.Reference beam optical system in this embodiment has telecentric optical system that a mask that is used for dwindling luminous flux 16, one be made up of lens 17 and 18, and diffraction grating 111, and, and therefore in Figure 14, save the structure in the downstream of diffraction grating 111 identical with in Fig. 8.
Secondly, will the operation of this embodiment be described.Mask 16 and diffraction grating 111 are arranged with mutual imaging relations, are made telecentric optical system between it.As a result, the opening portion of mask 16 is apparent on the diffraction grating 111, thereby collision becomes by the reference beam in the scope of opening portion restriction at the reference beam on the diffraction grating 111 200.
For example, at diffraction grating 111 are occasions of the type represented among Figure 12, what (1) possibility was necessary is, at least be sized to the scope of reference beam 200 irradiation diffraction grating 111 and be included among the cut zone N who represents among Figure 15 (in order to simplify, save the telecentric optical system that constitutes by lens 17 and 18, and structure is consistent with Figure 16).In addition, what (2) possibility was necessary is, the scope with reference beam 200 irradiations relevant with the size of cut zone N is such, make that the time be used for scanning the border between cut zone N and cut zone N+1 is short as much as possible, and the unsettled time of the deflection angle of reference beam 200 is short as much as possible.In addition, what (3) may be necessary is to shine the scope of the scope covering of hologram recording materials with the signal beams irradiation with reference beam 200.In addition, what (4) possibility was necessary is, the part of the stronger and more flat reference beam 200 of intensity is used as reference beam 200, partly shine hologram recording material with needs only with reference beam 200, prevent that thus hologram recording material 14 from be there is no need ground sensitization, and guarantee the dynamic range of hologram recording material 14 thus.Therefore, has the beam diameter of necessary adjusting reference beam 200 so that be met the suitable beam sizes of these four conditions; In this embodiment, the size of the opening portion by changing mask 16 can be easily and accurately realize regulating.
Explanation in passing can be adopted than simpler structure in this embodiment, in this structure, as shown in Figure 16, saves telecentric optical system, and mask 16 is positioned near diffraction grating 111, can obtain effect same as described above whereby.
[example 6]
Figure 17 is a calcspar, and expression is according to the structure of a reference beam optical system of a kind of hologram recording apparatus of sixth embodiment of the invention.The reference beam optical system of the hologram recording apparatus of angle multiplex system is finely tuned telecentric optical system that mirror 20, one be made of lens 21 and 22, mask 16, telecentric optical system that is made of lens 17 and 18, and diffraction grating 121 with an angle, and the structure in the downstream of diffraction grating 121 identical with in Fig. 8.
Secondly, the operation of this embodiment will be described below.Angle fine setting mirror 20 and mask 16 are arranged to be in mutual imaging relations, the telecentric optical system that is made of lens 21 and 22 are arranged between it.The path of reference beam 200 is changed by angle fine setting mirror 20, and reference beam 200 is imported into lens 22.When changing the angle of angle fine setting mirror 20, the path of reference beam 200 is changed one and changes corresponding to amount with angle, and reference beam 200 is imported into the telecentric optical system that is made of lens 21 and 22, to shine mask 16 immediately.Yet, because angle fine setting mirror 20 and mask 16 are in imaging relations, so by mask 16 dwindle and from the angle of its reference beam that comes out 200 because the angle of angle fine setting mirror 20 changes and is changed similarly, and reference beam 200 is incident on the telecentric optical system that is made of lens 17 and 18.Because mask 16 and diffraction grating 111 are in imaging relations, reformed angle is incident on the diffraction grating 111 so reference beam 200 changes with the angle according to the light beam that comes out from mask 16.This guarantees to pass through adjusting angle fine setting mirror 20 subtly, can change the incident angle of reference beam 200 on hologram recording material subtly.
According to this embodiment, can obtain following advantage.Under the situation of the diffraction grating of in using Figure 12 A and 12B, representing that is used for stepping deflection 121, if the contraction of the hologram recording material that the optimal incident angle in fact of reference beam 200 on hologram recording material causes owing to the position deviation of optical element part or by temperature variation etc. departs from, then the image of Zai Xianing can be darker.Yet, by regulating the incident angle of reference beam 200 on hologram recording material subtly, can realize a kind of angularity correction by angle fine setting mirror 20, can reproduce image all the time whereby with good quality.
[example 7]
Figure 18 A and 18B are calcspars, and expression is according to the structure of a reference beam optical system of a kind of hologram recording apparatus of the 7th embodiment.Figure 18 A represents that eliminating the telecentric optical system and the close diffraction grating 111 that are made of lens 17 and 18 by the structure of representing from Figure 16 arranges a kind of structure that mask 16 obtains.Figure 18 B represents by remove a kind of structure that the telecentric optical system that is made of lens 21 and 22 obtains from the structure of Figure 18 A.A kind of like this structure simplified size and the weight that is hopeful to reduce the quantity of optical element part and reduces adapter, but the problem at optical axis deviation center is arranged when rotational angle fine setting mirror 20.Yet, if the adjusting angle of angle fine setting mirror 20 is very little, even also can provide than simple structure shown in Figure 18 B is suitable for actual performance and the effect of using.
Explanation in passing, although the fine setting by the incident angle of reference beam 200 on hologram recording material has realized the optimized image reproduction in this embodiment, but, also can obtain identical effect by means of the incident angle of the layout angle by the hologram recording material 14 shown in meticulous adjusting Figure 19 with the meticulous adjusting reference beam 200 of relative mode.
Explanation the invention is not restricted to the foregoing description in passing, and in not breaking away from such scope of main points of the present invention, can realize with other variety of way about concrete structure, function, effect and effect.For example, although diffractive optical device is as holography scanner in above embodiment, a kind of acousto-optic device can be used for producing same effect.
Claims (22)
1. hologram recording apparatus, by an angle multiplex system at record on the holographic recording medium under the hold mode by in the interference fringe that interference produced between a signal beams and the reference beam, wherein in the incident angle on described holographic recording medium variation
The range of exposures fixed part is provided, is used for making the scope substantially constant that shines described holographic recording medium with described reference beam.
2. hologram recording apparatus according to claim 1, wherein, described range of exposures fixed part is that the beam diameter that is used for regulating the beam diameter of described reference beam is regulated part, and described beam diameter is regulated part and is provided in the reference beam optical system.
3. hologram recording apparatus according to claim 2, wherein, described beam diameter is regulated the operation of part with an angular deflection device of the described incident angle that is used for changing described reference beam, regulates the described beam diameter of described reference beam.
4. hologram recording apparatus according to claim 3, wherein, it is a diaphragm that described beam diameter is regulated part, and at described angular deflection device is under the situation of a scanning mirror, and described beam diameter is regulated the layout angle that partly changes described diaphragm with the angle variation of described scanning mirror.
5. hologram recording apparatus according to claim 1, wherein, described range of exposures fixed part comprises: diaphragm, it is arranged regularly; A lens combination with the telecentric imaging optical system is used for shining described diaphragm with described reference beam.
6. hologram recording apparatus according to claim 5, wherein, by making the described lens combination of the described telecentric imaging optical system be used for shining described holographic recording medium arrange with respect to an inclined light shaft ground, make described interference by described diaphragm, position relation between described holographic recording medium and described diaphragm so is provided with, and makes described holographic recording medium and described diaphragm satisfy the Shcheimpflug rule.
7. hologram recording apparatus according to claim 1, wherein, intensity adjustments partly makes at the intensity of the described reference beam in described range of exposures on described holographic recording medium substantially constant all the time.
8. hologram recording method, by an angle multiplex system at record on the holographic recording medium by in the interference fringe that interference produced between a signal beams and the reference beam in the incident angle on described holographic recording medium variation, described method comprises the step of regulating the beam diameter of described reference beam according to the variation of the described incident angle of described reference beam.
9. hologram recording apparatus according to claim 1, wherein,
Described holographic recording medium and a diffractive optical device arrange with imaging relations, constituting a telecentric optical system, and
Described range of exposures fixed part is a diffraction grating, and this diffraction grating has the diffraction grating gap of a variation.
10. hologram recording apparatus according to claim 9, wherein, described diffraction grating gap has one with respect to deflection angle continually varying diffraction grating gap.
11. hologram recording apparatus according to claim 9, wherein, described diffraction grating gap has a diffraction grating gap with respect to the deflection angle Discrete Change.
12. hologram recording apparatus according to claim 9, wherein, described diffractive optical device is a diffraction grating, its diffraction grating gap has one with respect to by cutting apart the diffraction grating gap of cutting apart the angle Discrete Change that deflection angle obtains, and changes very little in the same diffraction grating gap of cutting apart in the angle.
13. hologram recording apparatus according to claim 9, wherein, the diffraction efficiency of described diffractive optical device changes based on each deflection angle.
14. hologram recording apparatus according to claim 9, wherein, the described reference beam optical system that described reference beam advances therein comprises the optical system of the beam diameter that is used for limiting described reference beam.
15. hologram recording apparatus according to claim 14, wherein, the described optical system that is used for limiting the beam diameter of described reference beam has the diaphragm that is used for dwindling described reference beam.
16. hologram recording apparatus according to claim 15, wherein, described diaphragm is arranged near described diffractive optical device, and described telecentric optical system is between it.
17. hologram recording apparatus according to claim 15, wherein, described diaphragm is arranged near described diffractive optical device.
18. hologram recording apparatus according to claim 9, wherein, described reference beam optical system comprises the opticator of the fine setting of the angle that is used for described reference beam.
19. hologram recording apparatus according to claim 9, wherein, the described opticator of fine setting that is used for the angle of described reference beam is the scanning mirror that is used for changing the path of described reference beam, and described scanning mirror is arranged in the described reference beam optical system light source side at described diffractive optical device.
20. hologram recording apparatus according to claim 19, wherein, a mask is arranged near described diffractive optical device.
21. hologram recording apparatus according to claim 19, wherein, a mask is arranged near described diffractive optical device, and described telecentric optical system is between it.
22. hologram recording apparatus according to claim 11, wherein, a scanning mirror is arranged in the described diffractive optical device, and described telecentric optical system is between it.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004200387 | 2004-07-07 | ||
| JP2004200387A JP2006023445A (en) | 2004-07-07 | 2004-07-07 | Hologram recording apparatus and hologram recording method |
| JP2004265078 | 2004-09-13 |
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| CN1734587A true CN1734587A (en) | 2006-02-15 |
| CN100461276C CN100461276C (en) | 2009-02-11 |
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| CNB2005100832526A Expired - Fee Related CN100461276C (en) | 2004-07-07 | 2005-07-07 | Hologram recording apparatus and hologram recording method |
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| JP (1) | JP2006023445A (en) |
| CN (1) | CN100461276C (en) |
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| CN102394071A (en) * | 2006-11-01 | 2012-03-28 | 英法塞技术公司 | Monocular holographic data storage system architecture |
| CN101517644B (en) * | 2006-11-01 | 2012-05-09 | 三星电子株式会社 | Method and apparatus for recording and/or reproducing data to and/or from a holographic storage medium |
| CN101359484B (en) * | 2007-08-01 | 2012-11-07 | 索尼株式会社 | Hologram recording/reconstructing apparatus |
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| US7852538B2 (en) | 2004-07-07 | 2010-12-14 | Sony Corporation | Hologram recording apparatus and hologram recording method |
| JP2006078942A (en) * | 2004-09-13 | 2006-03-23 | Sony Corp | Hologram recording apparatus |
| JP4821216B2 (en) * | 2005-08-30 | 2011-11-24 | パルステック工業株式会社 | Hologram reproduction method |
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| US5436867A (en) * | 1993-03-08 | 1995-07-25 | Northrop Grumman Corporation | Holographic random access memory |
| US5777760A (en) * | 1996-05-10 | 1998-07-07 | Quantum Corporation | Position feedback system for volume holographic storage media |
| US5896359A (en) * | 1997-03-18 | 1999-04-20 | Northrop Grumman Corporation | Spinning disc volume holographic memory |
| JPH11353422A (en) * | 1998-06-04 | 1999-12-24 | Victor Co Of Japan Ltd | Information reader for optical recording medium |
| CN1242530A (en) * | 1998-07-03 | 2000-01-26 | 索尼株式会社 | Holographic stereogram creating apparatus and method |
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| CN102394071A (en) * | 2006-11-01 | 2012-03-28 | 英法塞技术公司 | Monocular holographic data storage system architecture |
| CN101517644B (en) * | 2006-11-01 | 2012-05-09 | 三星电子株式会社 | Method and apparatus for recording and/or reproducing data to and/or from a holographic storage medium |
| CN101359484B (en) * | 2007-08-01 | 2012-11-07 | 索尼株式会社 | Hologram recording/reconstructing apparatus |
| CN101740051B (en) * | 2008-11-26 | 2013-03-13 | 日立民用电子株式会社 | Optical information reproducing apparatus, optical information recording and reproducing apparatus |
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Also Published As
| Publication number | Publication date |
|---|---|
| JP2006023445A (en) | 2006-01-26 |
| CN100461276C (en) | 2009-02-11 |
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