CN117524266A

CN117524266A - Holographic storage device

Info

Publication number: CN117524266A
Application number: CN202210997377.3A
Authority: CN
Inventors: 郑智元
Original assignee: Qingdao Techgo Photoelectric Engineering Technology Co ltd
Current assignee: Qingdao Techgo Photoelectric Engineering Technology Co ltd
Priority date: 2022-07-29
Filing date: 2022-08-19
Publication date: 2024-02-06

Abstract

A holographic storage device comprising a light emitter, a spatial light modulator (spatial lightmodulator; SLM), an objective lens and an actuator. The spatial light modulator is optically coupled to the light emitter. The objective lens is optically coupled to the spatial light modulator and aligned with the storage disk, and the objective lens includes a super surface focusing lens (metasurface focusing lens), wherein the super surface focusing lens has an optical axis that extends along a first direction. The actuator is connected with the objective lens and is used for enabling the objective lens to move along a first direction. With the above configuration, since the objective lens configured by the super-surface focusing lens can have a smaller size and a lighter weight, the change of the data reading or writing depth of the holographic storage device to the storage disk can be realized by moving the objective lens, thereby improving the accuracy and reliability of the reading or writing procedure.

Description

Holographic storage device

Technical Field

The present invention relates to a holographic storage device.

Background

Along with the development of technology, the required storage amount of electronic files is also increased. A common storage method is to record magnetic or optical changes on the surface of a storage medium, as a basis for stored data, such as a magnetic disk or optical disk. However, as the required storage volume of electronic files increases, the technical development of holographic storage is beginning to be spotlighted. The holographic storage technology is to write the image data into the storage medium after the interference generated by the optical signal and the reference light. When the data is read, the image data can be generated by re-irradiating the reference light onto the storage medium. Then, the generated image data is read by the detector. In this regard, how to improve the accuracy or reliability of a writing process or a reading process has been the subject of current research in the related art.

Disclosure of Invention

The technical scheme of the invention is realized as follows:

a holographic storage device, comprising: a light emitter, a spatial light modulator (spatial light modulator; SLM), an objective lens and an actuator. The spatial light modulator is optically coupled to the light emitter. The objective lens is optically coupled to the spatial light modulator and aligned with the storage disk, and the objective lens includes a super surface focusing lens (metasurface focusing lens), wherein the super surface focusing lens has an optical axis that extends along a first direction. The actuator is connected with the objective lens and used for enabling the objective lens to move along a first direction.

In some embodiments, the holographic storage device further comprises a polarizing beamsplitter and a carrier. The polarizing beamsplitter is optically coupled between the spatial light modulator and the objective lens. The distance between the bearing table and the polarization spectroscope in the first direction is fixed and is used for bearing the storage disc.

In some embodiments, the holographic storage device further comprises a controller. The controller is electrically connected with the brake and used for controlling the brake so as to adjust the height of the objective lens relative to the storage disc through the brake.

In some embodiments, the light emitter includes a laser light source for emitting a light beam having a single wavelength.

In some embodiments, the single wavelength value of the beam is 532 nm.

In some embodiments, the holographic storage device further comprises a metasurface lens (metasurface lens) optically coupled between the light emitter and the holographic storage disk objective lens.

In some embodiments, the objective lens has opposite light entrance and exit ends, and only a super-surface focusing lens is present between the light entrance and exit ends of the objective lens.

In some embodiments, the super-surface focusing lens has a periodically arranged microstructure array.

In some embodiments, the holographic storage device further comprises a polarizing beamsplitter, an imaging lens, and a photodetector. The polarizing beamsplitter is optically coupled between the spatial light modulator and the objective lens. The imaging lens is optically coupled between the polarizing beamsplitter and the photodetector.

In some embodiments, the holographic storage device further comprises a polarizing beamsplitter and a photodetector. The objective lens is optically coupled between the spatial light modulator and the holographic storage disk, and the objective lens is also optically coupled between the holographic storage disk and the photodetector.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:

fig. 1A is a schematic optical path diagram of a holographic storage device according to a first embodiment of the present disclosure.

FIG. 1B is an enlarged schematic view of the objective lens, the actuator and the storage disk on the stage of FIG. 1A.

Fig. 2 is a schematic light path diagram of a holographic storage device according to a second embodiment of the present disclosure.

Reference numerals illustrate:

100A, 100B holographic storage device

102. Storage disk

110. Bearing table

112. Rotator

114. Displacement device

120. Light emitter

122. Spatial light modulator

130. Objective lens

132. Super-surface focusing lens

133. Optical axis

134. Microstructure array

140. First lens

142. First reflecting mirror

144. First polarizing beam splitter

146. Second lens

148. Second polarizing beam splitter

150. Third lens

152. Quarter wave plate

154. Second reflecting mirror

156. Third reflecting mirror

158. Fourth lens

160. Photodetector

162. Controller for controlling a power supply

170. Brake device

172. Mobile rail

174. Lifting device

176. Connecting piece

180. Fifth lens

182. Fourth reflecting mirror

183. Third polarizing beam splitter

184. Half wave plate

186. Fourth polarizing spectroscope

188. Fifth reflecting mirror

190. Vibrating mirror

192. Seventh lens

194. Fifth polarizing spectroscope

L1, L4 beam

L2, L5 servo read light

L3, L6 servo diffraction light

Detailed Description

The present disclosure will be clearly described in the following drawings and detailed description, and any person skilled in the art, having the knowledge of the preferred embodiments of the present disclosure, may make variations and modifications by the techniques disclosed in the present disclosure, without departing from the spirit and scope of the present disclosure.

The terms first, second, third, etc. are used herein to describe various components, regions and/or layers and should be understood. But such components, regions and/or layers should not be limited by such terms. These terms are limited to use to identify individual components, regions, and/or layers. Accordingly, a first component, region, and/or layer could also be termed a second component, region, and/or layer below without departing from the teachings of the present application.

Fig. 1A is a schematic optical path diagram of a holographic storage device 100A according to a first embodiment of the present disclosure, wherein the holographic storage device 100A shown in fig. 1A is for reading data from a storage disk 102.

As shown in fig. 1A, holographic storage device 100A includes a stage 110, a light emitter 120, a spatial light modulator (spatial light modulator; SLM) 122, an objective lens 130, a first lens 140, a first mirror 142, a first polarizing beamsplitter 144, a second lens 146, a second polarizing beamsplitter 148, a third lens 150, a quarter wave plate 152, a second mirror 154, a third mirror 156, a fourth lens 158, a light detector 160, a controller 162, and an actuator 170.

The stage 110 may be configured to carry the storage disk 102, and the stage 110 may include a rotator 112 and a displacer 114. The carrying platform 110 may drive the storage disc 102 to rotate through the rotator 112, and may also drive the storage disc 102 to move along a horizontal plane where the storage disc 102 is located (i.e. along a direction of an extension surface of the storage disc 102) through the shifter 114, so as to facilitate the holographic storage device 100A to store or read data from the storage disc 102. The storage disk 102 may include a storage layer (not shown) formed of a photosensitive material, and the storage layer may record data content, such as alignment data or page data, by generating an interference pattern therein by beam interference. In addition, the storage disk 102 is removable with respect to the carrier 110.

The holographic storage device 100A may provide a light beam through its optical components and direct the light beam onto the storage disk 102 to resolve data content according to an interference pattern within the storage disk 102, as will be further described below with respect to the optical components of the holographic storage device 100A.

The light emitter 120 may include a laser light source, wherein the laser light source is configured to emit a light beam L1, and the light beam L1 has a single wavelength. In some embodiments, the single wavelength of the light beam L1 provided by the light emitter 120 through the laser light source is 532 nm. Here, the single wavelength value of the light beam L1 of 532 nm may be: the light beam L1 presents pulses at 532 nanometers on the wavelength spectrum of the light intensity; alternatively, the light intensity of the light beam L1 may exhibit a gaussian distribution with a narrow bandwidth (e.g., a length distribution of less than 1 nm or 2 nm) at 532 nm, and the peak value thereof corresponds to 532 nm.

The first lens 140, the first mirror 142, and the first polarizing beamsplitter 144 may be optically coupled between the light emitter 120 and the spatial light modulator 122 such that the light beam L1 emitted from the light emitter 120 may be directed to the spatial light modulator 122. That is, the spatial light modulator 122 may optically couple the light emitter 120 through the first lens 140, the first mirror 142, and the first polarizing beamsplitter 144. The first lens 140 may be a focusing lens and convert the light beam L1 from the light emitter 120 into parallel light, and the first mirror 142 may adjust the traveling direction of the light beam L1 to be aligned with the first polarization beam splitter 144. When the light beam L1 travels to the first polarizing beamsplitter 144, at least a portion of the light beam L1 is diverted by the first polarizing beamsplitter 144 to travel toward the spatial light modulator 122 and then enter the spatial light modulator 122.

The spatial light modulator 122 may be used to modulate the properties of the received light beam L1 through the liquid crystal molecules such that the light beam L1 may be modulated into an optical signal, a reference light, or a servo read light. In some embodiments, the spatial light modulator 122 may be a liquid crystal on silicon (liquid crystal on silicon; LCoS). Specifically, after the spatial light modulator 122 receives the light beam L1 from the first polarizing beam splitter 144, the spatial light modulator 122 modulates the light beam L1 into the servo read light L2, and provides the servo read light L2 to the first polarizing beam splitter 144, such that at least a portion of the servo read light L2 passes through the first polarizing beam splitter 144.

The second lens 146, the second polarizing beamsplitter 148, the third lens 150, the quarter wave plate 152, and the second mirror 154 may be optically coupled between the first polarizing beamsplitter 144 and the objective lens 130 (i.e., between the spatial light modulator 122 and the objective lens) such that the servo read light L2 passing through the first polarizing beamsplitter 144 may be directed to the objective lens 130. Specifically, the servo read light passing through the first polarizing beamsplitter 144 may travel through a second lens 146, wherein the second lens 146 may be a focusing lens and convert the servo read light L2 from the first polarizing beamsplitter 144 into a focused beam and travel toward a second polarizing beamsplitter 148.

The second polarizing beamsplitter 148 is positioned to optically couple the focal point of the second lens 146, e.g., to optically couple the focal point of the second lens 146. When the servo read light L2 travels to the second polarization beam splitter 148, at least a portion of the servo read light L2 passes through the second polarization beam splitter 148 and travels toward the third lens 150, wherein the third lens 150 may be a focusing lens, and the third lens 150 may be disposed at a position that is optically coupled to a focusing point of the second lens 146, for example, the focal points of the second lens 146 and the third lens 150 may coincide with each other, so that the servo read light L2 entering the third lens 150 may be parallel incident to the quarter wave plate 152 and the second reflecting mirror 154. The quarter wave plate 152 may generate a quarter phase difference to the servo read light L2 passing therethrough, and the second mirror 154 may adjust the traveling direction of the servo read light L2 from the quarter wave plate 152 to be aligned with the objective lens 130.

With the above configuration, the image plane of the spatial light modulator 122 can be equivalently moved before the objective lens 130, so that the objective lens 130 can be optically coupled to the spatial light modulator 122, so that the objective lens 130 projects the servo reading light L2 onto the storage disc 102 on the stage 110. Specifically, objective lens 130 may be aligned with storage disk 102 on stage 110 to focus servo read light L2 from spatial light modulator 122 onto storage disk 102.

Referring to fig. 1A and fig. 1B, fig. 1B is an enlarged schematic view of the objective lens 130, the actuator 170 and the storage disc 102 on the stage 110 in fig. 1A. The objective lens 130 may include a super surface focusing lens 132 (metasurface focusing lens), wherein the super surface focusing lens 132 has an optical axis 133, and the optical axis 133 extends along a first direction D1, wherein the first direction D1 is a direction (or opposite direction) from the super surface focusing lens 132 toward the storage disk 102 or the turntable 110, i.e., the optical axis 133 of the super surface focusing lens 132 passes through at least the storage disk 102. The super surface focusing lens 132 may focus the servo read light L2 from the spatial light modulator 122 into a spot focused on the storage disk 102. In this regard, the super-surface focusing lens 132 may have a periodically arranged micro-structure array 134, and the micro-structure array 134 may guide the servo read light L2, so that the super-surface focusing lens 132 has an effect of focusing light, and further, the super-surface focusing lens 132 may be equivalent to have a negative refractive index through the micro-structure array 134, thereby achieving the effect of focusing light.

The micro-structure array 134 of the super-surface focusing lens 132 may be formed by arranging a plurality of nano-structures or may be formed by arranging a plurality of grating patterns, and the focusing effect may possibly cause aberration due to the difference of wavelength distribution by using the micro-structure array 134 to guide light. For example, when light of different wavelength values passes through the super surface focusing lens 132, the light of different wavelength values may be focused at different depths, resulting in aberration. In this regard, since the light beam L1 provided by the light emitter 120 of the holographic storage device 100A may be a single wavelength, the micro-structured array 134 of the super-surface focusing lens 132 is used to guide the servo read light L2 and focus the servo read light L2 on the storage disc 102, so as to avoid being affected by aberration. In addition, because the super-surface focusing lens 132 directs the servo read light L2 to focus on the storage disk 102 through the micro-structure array 134, the super-surface focusing lens 132 can be smaller in size and lighter in weight. For example, when a solid transparent material (e.g., glass) is used to equivalently create a guide for servo read light L2 to focus on storage disk 102, the size or weight of an optical assembly made of the solid transparent material will be relatively larger than that of super-surface focusing lens 132. In this way, the objective lens 130 configured by the super-surface focusing lens 132 can have a smaller size, thereby facilitating miniaturization of the entire volume of the holographic storage device 100A.

On the other hand, when areas of different depths of the storage disk 102 are to be read during data reading of the storage disk 102 by the holographic storage device 100A, the distance between the objective lens 130 and the storage disk 102 in the first direction D1 may be changed, thereby changing the data reading depth of the storage disk 102 by the holographic storage device 100A. In the case where the objective lens 130 is configured using the super surface focusing lens 132, since the objective lens 130 having a small size and a light weight can be easily moved, the actuator 170 can be connected to the objective lens 130, thereby moving the objective lens 130 along the first direction D1 through the actuator 170.

The brake 170 may include a moving rail 172, a lifter 174, and a connection member 176, wherein the moving rail 172 extends along the first direction D1, and the lifter 174 may be connected to the moving rail 172 and include a motor, such as a speed-adjusting motor, a stepping motor, or a servo motor. The connection member 176 is connected between the lifter 174 and the objective lens 130, such that when the lifter 174 moves along the first direction D1 on the moving rail 172, the objective lens 130 is driven to move along the first direction D1 through the connection member 176.

The controller 162 is electrically connected to the lifter 174 of the actuator 170, and is used to control the extent to which the lifter 174 of the actuator 170 moves the objective lens 130 along the first direction D1. In other words, the controller 162 may be configured to control the elevator 174 of the actuator 170, thereby adjusting the height of the objective lens 130 relative to the storage disc 102 via the elevator 174 of the actuator 170. In this way, when the objective lens 130 moves along the first direction D1, the height of the objective lens 130 relative to the storage disc 102 is changed, so as to change the data reading depth of the holographic storage device 100A on the storage disc 102.

Since the process of changing the data reading depth of the holographic storage device 100A to the storage disc 102 is implemented by adjusting the height of the objective lens 130 relative to the storage disc 102, and the storage disc 102 is not required to be displaced in the first direction D1 during the adjustment, the situation that the storage disc 102 is distorted due to the displacement is avoided, and thus the accuracy and reliability of the data reading procedure are improved. Further, during the process of changing the data reading depth of the holographic storage device 100A to the storage disc 102, the distance between the stage 110 and the second polarization beam splitter 148 in the first direction D1 may be fixed.

In some embodiments, the objective lens 130 may be formed by a single super-surface focusing lens 132, and in particular, the objective lens 130 may have an opposite light entrance end and light exit end, wherein the light entrance end faces the second mirror 154 and the light exit end faces the storage disk 102, and only the single super-surface focusing lens 132 is disposed between the light entrance end and the light exit end. In other embodiments, the objective lens 130 may be a lens group formed by a plurality of super-surface focusing lenses, or a lens group formed by at least one super-surface focusing lens and at least one solid material lens.

The servo read light L2 projected to the storage disk 102 by the objective lens 130 can be formed into servo diffracted light L3 in the storage disk 102 and reflected from the storage disk 102. The servo diffracted light L3 may travel along the original optical path back to the second polarization beam splitter 148, and the quarter wave plate 152 may generate a quarter phase difference for the servo diffracted light L3 passing through it on the way the servo diffracted light L3 travels from the storage disk 102 to the second polarization beam splitter 148, so that a half phase difference exists between the servo diffracted light L3 and the servo read light L2 originally passing through the second polarization beam splitter 148, so that at least a portion of the servo diffracted light L3 is diverted by the second polarization beam splitter 148.

The third mirror 156 and the fourth lens 158 may be optically coupled between the second polarization beam splitter 148 and the light detector 160, such that the servo diffracted light L3 diverted from the second polarization beam splitter 148 may travel to the light detector 160 via the third mirror 156 and the fourth lens 158, wherein the fourth lens 158 may be a focusing lens, and the fourth lens 158 may also be disposed at a position that optically couples the focusing point of the second lens 146, for example, the focusing points of the second lens 146 and the fourth lens 158 may coincide with the same point via the third mirror 156, such that the servo diffracted light L3 reflected by the third mirror 156 and entering the fourth lens 158 may be converted into parallel light after passing through the fourth lens 158 and enter the light detector 160. In other words, the fourth lens 158 may be used as an imaging lens to enable the servo diffracted light L3 to form an image on the photodetector 160, wherein the photodetector 160 may be a photosensitive device, such as a charge-coupled device (CCD) or a metal oxide semiconductor (complementary metal oxide semiconductor; CMOS) photodetector. The photodetector 160 can read the image formed by the servo diffraction light L3 and generate corresponding data according to the analysis result.

The arrangement of components in holographic storage device 100A shown in FIG. 1A is illustrative only and is not limiting of the relationship of components in holographic storage device 100A of the present disclosure. In other embodiments, the components of the first lens 140, the second lens 146, the third lens 150 or the fourth lens 158 used as the retarder or the imaging lens may be replaced with a lens made of a meta-material (meta-material), for example, the first lens 140 optically coupled between the light emitter 120 and the objective lens 130 may be replaced with a super-surface lens (meta-surface lens), which has a high Numerical Aperture (NA) and a reduced volume, so that the structural configuration of the holographic storage device 100A may be more compact, thereby facilitating the miniaturization of the whole volume of the holographic storage device 100A.

In addition, in the present embodiment, although the relative positional relationship between the objective lens 130 and the storage disc 102 along the extending direction of the storage disc 102 is adjusted by the shifter 114, but not limited thereto, in other embodiments, since the objective lens 130 with smaller size and lighter weight can be easily moved, the shifter 114 may be changed to be connected to the objective lens 130, so that the shifter 114 can drive the objective lens 130 to move along the horizontal plane perpendicular to the first direction D1.

Although the holographic storage device 100A of the first embodiment of the present disclosure is configured to be in a coaxial configuration, the present disclosure is not limited thereto, and the holographic storage device may be configured to be in an off-axis configuration in other embodiments.

For example, as shown in fig. 2, fig. 2 is a schematic light path diagram of a holographic storage device 100B according to a second embodiment of the disclosure, wherein the holographic storage device 100B shown in fig. 2 is for reading data from a storage disc 102. As shown in fig. 2, at least one point of difference between the present embodiment and the first embodiment is that the holographic memory device 100B of the present embodiment is configured off-axis. Specifically, holographic storage device 100B includes stage 110, light emitter 120, spatial light modulator 122, objective lens 130, fifth lens 180, fourth mirror 182, third polarizing beamsplitter 183, half wave plate 184, fourth polarizing beamsplitter 186, fifth mirror 188, galvanometer 190, seventh lens 192, fifth polarizing beamsplitter 194, light detector 160, controller 162, and actuator 170, wherein objective lens 130 is optically coupled between spatial light modulator 122 and fifth polarizing beamsplitter 194, and fifth polarizing beamsplitter 194 is optically coupled between objective lens 130 and light detector 160.

The light beam L4 emitted by the light emitter 120 can be guided to the spatial light modulator 122 through the fifth lens 180, the fourth mirror 182, the third polarizing beam splitter 183, so that the light beam L4 can be modulated into the servo read light L5, and the servo read light L5 can be further guided to the objective lens 130 through the half wave plate 184, the fourth polarizing beam splitter 186, the fifth mirror 188, the galvanometer 190 and the seventh lens 192.

Likewise, the objective lens 130 may include a super-surface focusing lens 132 such that the servo read light L5 may be focused into a spot focused on the storage disk 102 and into a servo diffracted light L6 within the storage disk 102. Then, the servo diffracted light L6 is reflected from the storage disc 102 and is guided to the light detector 160 through the objective lens 130 and the fifth polarizing beam splitter 194, so that the light detector 160 can read the image formed by the servo diffracted light L6 and generate corresponding data according to the analysis result. As described above, in the case where the objective lens 130 is configured by using the super-surface focusing lens 132 and thus has a smaller size and a lighter weight, the actuator 170 may be connected to the objective lens 130, so that the controller 162 may control the actuator 170 to adjust the height of the objective lens 130 relative to the storage disc 102, and the description of this embodiment may be the same or similar to that of the first embodiment, and will not be repeated herein.

In the present application, the manner in which the optical path of the holographic storage device is established is shown only schematically, and is not intended to limit the arrangement of the components of the holographic storage device. In some embodiments, the delay of the image in the optical path may be changed, for example, a lens may be added or an original lens may be removed from the optical path, so as to increase or decrease the optical path length.

In addition, in the present application, the holographic storage device is described in a manner of reading data from the storage disc, but the present application is not limited thereto. In other words, in response to other requirements of the holographic storage device, such as data writing requirements, the objective lens is connected to the optical disc, so that the objective lens projects the data light and the reference light onto the optical disc, and the height of the objective lens relative to the optical disc can be adjusted by the actuator, so that the data writing depth of the holographic storage device to the optical disc can be changed.

In summary, the holographic storage device of the present disclosure includes an optical emitter, a spatial light modulator, an objective lens, and an actuator. The spatial light modulator may be optically coupled between the light emitter and the objective lens and configured to modulate a light beam provided by the light emitter. The light beam modulated by the spatial light modulator may be directed to an objective lens, wherein the objective lens is directed to the storage disk and includes a super-surface focusing lens, such that the light beam is focused into a spot focused on the storage disk by the super-surface focusing lens, thereby facilitating writing or reading of the storage disk by the holographic storage device. The actuator is connected with the objective lens. In this regard, since the objective lens configured by the super-surface focusing lens can have a smaller size and a lighter weight, the actuator can advantageously adjust the height of the objective lens relative to the storage disk by moving the objective lens, thereby advantageously changing the data reading (or writing) depth of the holographic storage device to the storage disk. In addition, since the change of the data reading (or writing) depth of the holographic storage device to the storage disk can be realized by moving the objective lens, the accuracy and reliability of the reading procedure (or writing procedure) can be improved.

While the present disclosure has been described with reference to the embodiments, it should be understood that the invention is not limited thereto but may be variously modified or altered by those skilled in the art without departing from the spirit and scope of the present disclosure, and thus the scope of the present disclosure is defined by the appended claims.

Claims

1. A holographic storage device, comprising:

a light emitter;

a spatial light modulator (spatial light modulator; SLM) optically coupled to the light emitter;

an objective lens optically coupled to the spatial light modulator and aligned with a storage disk, the objective lens comprising a super surface focusing lens (metasurface focusing lens), wherein the super surface focusing lens has an optical axis extending along a first direction; and

and a brake connected with the objective lens for moving the objective lens along the first direction.

2. The holographic storage device of claim 1, further comprising:

a polarization spectroscope optically coupled between the spatial light modulator and the objective lens; and

the distance between the bearing table and the polarization beam splitter in the first direction is fixed, and the bearing table is used for bearing the storage disc.

3. The holographic storage device of claim 1, further comprising:

and the controller is electrically connected with the brake and is used for controlling the brake so as to adjust the height of the objective lens relative to the storage disc through the brake.

4. The holographic storage of claim 1, wherein,

the light emitter comprises a laser light source for emitting a light beam, and the light beam has a single wavelength and high coherence.

5. The holographic storage device of claim 1, further comprising:

a metasurface lens (metasurface lens) is optically coupled between the light emitter and the objective lens.

6. The holographic storage of claim 1, wherein,

the objective lens is provided with a light inlet end and a light outlet end which are opposite, and only the super-surface focusing lens is arranged between the light inlet end and the light outlet end of the objective lens.

7. The holographic storage of claim 1, wherein,

the super-surface focusing lens is provided with a microstructure array which is formed by periodical arrangement.

8. The holographic storage of claim 1, wherein,

the super-surface focusing lens can reach ideal focusing conditions under the designed working wavelength.

9. The holographic storage device of claim 1, further comprising:

a polarization spectroscope optically coupled between the spatial light modulator and the objective lens;

an imaging lens; and

and a photodetector, wherein the imaging lens is optically coupled between the polarizing beamsplitter and the photodetector.

10. The holographic storage device of claim 1, further comprising:

a polarizing beamsplitter, wherein the objective lens is optically coupled between the spatial light modulator and the polarizing beamsplitter; and

and a photodetector, wherein the polarizing beamsplitter is optically coupled between the objective lens and the photodetector.