Holographic storage optical system

Abstract

The invention discloses a holographic storage optical system, and relates to the field of holographic storage optics. The system comprises a first metasurface arranged on a light path of a write-in light beam with S polarization; the phase difference between the first polarized light and the polarization direction of the write-in light beam is 90 degrees, and the polarization direction of the second polarized light is consistent with the polarization direction of the write-in light beam, and the second polarized light has an off-axis focusing characteristic. The second metasurface is arranged on a light path of the second polarized light; the second metasurface is used for reflecting the second polarized light into parallel light; the mask plate is arranged on a light path of the parallel light; the mask has a target image; the third super-structure plane is arranged on a light path of the second polarized light; the parallel light passes through the mask plate and then enters the third super-structure plane; the third super-structure plane is used for focusing the parallel light emitted from the mask; the first polarized light and the focused polarized light intersect at an intersection point, and the photosensitive material is arranged at the intersection point. The structure of the holographic storage optical system is simplified.

Description

Technical Field

[0001] The invention relates to the technical field of holographic storage optics, and in particular to a holographic storage optical system. Background Art

[0002] At present, the total amount of data is increasing at a super-exponential rate, which has put forward an urgent need for the development of advanced information storage technology. In this context, optical storage technology has shown broad development prospects and huge application value with its significant advantages such as low energy consumption, long life and high-density storage. Among them, holographic optical storage technology is particularly eye-catching. Based on the principle of holography, this technology irradiates the storage medium through double-beam interference, so that the molecular, atomic or electronic states in the medium are periodically modulated by the light field, thereby changing the optical properties of the material. In this process, the entire page of data information is recorded in the form of alternating light and dark stripes. These stripe information not only contains the amplitude and phase information of the light, but also covers dimensions such as polarization, realizing parallel page-based recording. This innovative recording method breaks the limitations of traditional bit-based recording and effectively improves the density of optical storage and data processing speed. Therefore, it is regarded as a strong competitor for the next generation of storage technology.

[0003] In the process of realizing optical storage, it is usually necessary to construct the optical path by oneself, and record information by guiding the object light and the reference light to interfere with each other. This process often requires a complex combination of mirrors and lens barrels to achieve, which leads to a complex structure and bulky size of the optical system. Given that metasurfaces can flexibly control the amplitude, phase and polarization characteristics of light on a subwavelength scale, this provides a very potential solution for simplifying the structure of optical systems and reducing their size. Therefore, exploring the use of metasurface technology to achieve the miniaturization of holographic storage optical systems has become a key issue that needs to be solved urgently. Summary of the invention

[0004] The object of the present invention is to provide a holographic storage optical system, which can simplify the structure of the holographic storage optical system and realize the miniaturization of the holographic storage optical system.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A holographic storage optical system, the above system includes: a first metasurface, a second metasurface, a third metasurface, a mask, a photosensitive material, and a photoelectric detection device; the above first metasurface is arranged on the optical path of a writing beam with S polarization; the above first metasurface is used to divide the above writing beam into a first polarized light with a phase difference of 90° from the polarization direction of the above writing beam and a second polarized light with the same polarization direction as the above writing beam and having an off-axis focusing characteristic; the above second metasurface is arranged on the optical path of the above second polarized light; the above second metasurface is used to reflect the above second polarized light into parallel light; the above mask is arranged on the optical path of the above parallel light; the above mask has a target image; the above third metasurface is arranged on the optical path of the above second polarized light; the above parallel light is incident on the above third metasurface after passing through the above mask; the above third metasurface is used to focus the parallel light emitted from the above mask; the above first polarized light and the focused polarized light intersect at an intersection point, and the above photosensitive material is arranged at the above intersection point; on one side of the above photosensitive material, a detection beam with a preset wavelength is incident on the above photosensitive material from the above intersection point, and the above photoelectric detection device is used to receive the beam emitted from the other side opposite to one side of the above photosensitive material, so as to realize the reproduction of holographic image information.

[0007] Optionally, the above first metasurface includes a first substrate, a first subwavelength array, and a second subwavelength array; the above second metasurface includes a second substrate and a third subwavelength array; the above third metasurface includes a third substrate and a fourth subwavelength array; the above first metasurface includes a light incident side and a light exit side; the beam enters from the above light incident side and exits from the above light exit side; the above first subwavelength array and the above second subwavelength array are cross-arranged on the light exit side of the above first substrate; the above third subwavelength array is arranged on one side of the above second substrate; the above fourth subwavelength array is arranged on one side of the above third substrate.

[0008] Optionally, the above system further includes: a first laser and a second laser; the above first laser is used to provide a writing beam with S polarization; the above second laser is used to provide a detection beam with a preset wavelength.

[0009] Optionally, the above photoelectric detection device includes but is not limited to a photodetector, a photodiode, and a charge-coupled element.

[0010] Optionally, the materials of the above first substrate, the above first subwavelength array, and the above second subwavelength array are all materials with a light transmittance higher than a preset light transmittance in the visible light band; the material of the above second substrate is a material with a reflectance higher than a preset reflectance in the visible light band; the materials of the above third substrate, the above third subwavelength array, and the above fourth subwavelength array are all materials with a light transmittance higher than a preset light transmittance in the visible light band.

[0011] Optionally, the diameter of the light spot of the above-mentioned collimated light is greater than the diameter of the light spot of the second polarized light incident on the second metasurface.

[0012] Optionally, the above-mentioned first sub-wavelength array, the above-mentioned second sub-wavelength array, and the above-mentioned third sub-wavelength array are all rectangular column arrays with birefringence effect or elliptical column arrays with birefringence effect.

[0013] Optionally, the above-mentioned fourth sub-wavelength array is a polarization-insensitive cylindrical array, a rectangular column array with birefringence effect, or an elliptical column array with birefringence effect.

[0014] Optionally, the wavelengths of the above-mentioned writing beam and the above-mentioned detection beam are different.

[0015] Optionally, the wavelength range of the above-mentioned writing beam is from the visible band to the near-infrared band.

[0016] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention:

[0017] The present invention discloses a holographic storage optical system, which realizes the splitting of the writing beam by the first metasurface while respectively regulating the first polarized light and the second polarized light. The second metasurface regulates the wavefront of the second polarized light so that the reflected beam after beam expansion is perpendicular to the third metasurface, thereby replacing a relatively large beam expander group to realize the beam expansion function. The third metasurface realizes the focusing of the beam. The first polarized light and the beam focused by the third metasurface overlap at the same spatial position of the photosensitive medium, and optical interference occurs, thereby realizing optical storage. On one side of the photosensitive material, a detection beam with a preset wavelength is incident on the photosensitive material from the intersection point, and a photoelectric detection device is used to receive the beam exiting from the other side opposite to one side of the photosensitive material to obtain a holographic image, realizing the reading of information. The present invention realizes the miniaturization of the holographic storage optical system by using metasurfaces. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0019] Figure 1 It is the optical path diagram of the optical system for realizing miniaturized holographic storage by using metasurfaces in the present invention;

[0020] Figure 2 It is the schematic optical path diagram of the first metasurface for realizing polarization regulation, off-axis focusing and parallel output in the present invention;

[0021] Figure 3 Optical path schematic diagram of the second metasurface for expanding the object light in the present invention;

[0022] Figure 4 Optical path schematic diagram of the third metasurface for focusing the object light in the present invention. Detailed implementation manners

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] The purpose of the present invention is to provide a holographic storage optical system, aiming to simplify the structure of the holographic storage optical system and realize the miniaturization of the holographic storage optical system.

[0025] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0026] As Figure 1 shown, the holographic storage optical system in this embodiment includes: a first metasurface, a second metasurface, a third metasurface, a mask, and a photosensitive material; the first metasurface is arranged on the optical path of the writing beam with S polarization; the first metasurface is used to divide the writing beam into a first polarized light with a phase difference of 90° from the polarization direction of the writing beam and a second polarized light with the same polarization direction as the writing beam and having an off-axis focusing characteristic; the second metasurface is arranged on the optical path of the second polarized light; the second metasurface is used to reflect the second polarized light into parallel light; the mask is arranged on the optical path of the parallel light; the mask has a target image; the third metasurface is arranged on the optical path of the second polarized light; the parallel light is incident on the third metasurface after passing through the mask; the third metasurface is used to focus the parallel light emitted from the mask; the first polarized light and the focused polarized light intersect at an intersection point, and the photosensitive material is arranged at the intersection point; on one side of the photosensitive material, a detection beam with a preset wavelength is incident on the photosensitive material at the intersection point, and a photoelectric detection device is used to receive the light beam emitted from the other side opposite to one side of the photosensitive material to realize the reproduction of holographic image information. The diameter of the spot of the parallel light is larger than the diameter of the spot of the second polarized light incident on the second metasurface.

[0027] The holographic storage optical system further includes: a first laser and a second laser; the first laser is used to provide a write beam with S polarization; the second laser is used to provide a probe beam with a preset wavelength. The photoelectric detection device includes but is not limited to a photodetector, a photodiode, and a charge-coupled device.

[0028] In practical applications, after the write beam with S polarization is emitted, it is precisely split into two beams by the first metasurface, and these two beams exhibit nearly the same power density. One of the beams is the first polarized light, designated as the reference light, and after being regulated by the first metasurface, its polarization state is changed to the orthogonal P polarization. At the same time, the first metasurface also enables the other beam to have the characteristic of off-axis focusing, which is called the second polarized light and is designated as the object light. The object light diverges gradually after focusing and reaches the second metasurface. Here, the object light is reflected by the second metasurface into parallel light and then projected onto the photosensitive material. During this process, the object light and the reference light overlap at the same position on the photosensitive material and interfere. This interference process enables the photosensitive material to record the information of the wavefront. When a probe beam with a low-sensitivity wavelength irradiates the hologram position, based on the microstructure of the holographic grating, a diffraction phenomenon will occur, thereby changing the propagation property of the light. This modulation of the readout light is closely related to the previously recorded wavefront information, thus realizing the reproduction of the stored information.

[0029] Among them, the photosensitive material, as the recording medium of the holographic storage optical system, can record the interference pattern through the action of light and store data. The mask is used to modulate the light beam during the recording process to generate a specific light field distribution so as to form a hologram in the photosensitive material. The photoelectric detection device is used to receive and detect the optical signal read from the storage medium and convert it into an electrical signal for further processing. The write beam is usually emitted by a laser with a wavelength of 532 nm or 633 nm in the visible band. The probe beam is used to read the data stored in the photosensitive material. The probe beam irradiates the storage medium to reconstruct the stored hologram. The wavelength of the probe beam should avoid the photosensitive band of the recording medium to prevent the occurrence of a photoreaction that causes information erasure. Therefore, a wavelength of 780 nm or 830 nm can be selected.

[0030] The reference light and the focused object light intersect at an intersection point, and the photosensitive material is arranged at the intersection point; the object light and the reference light interfere at this point to form a hologram and store it in the recording photosensitive material.

[0031] When reading information, a probe beam with a preset wavelength is incident on the photosensitive material from the intersection point, and a photoelectric detection device is used to receive the light beam exiting from the photosensitive material from the other side opposite to the side where the probe beam is incident on the photosensitive material, reconstruct the hologram and convert it into an electrical signal through the detector, and finally processed and decoded by a computer.

[0032] The present invention can achieve the splitting of the writing beam by using only the first metasurface, and simultaneously precisely control the polarization characteristics of the reference light and the wavefront of the object light. Therefore, when the two beams of light leave the first metasurface, they each exhibit unique response characteristics: the reference light has a certain deflection angle and phase delay relative to the writing beam, while the object light has a deflection angle and focusing characteristics. The parallel emission of the diverging beam after focusing can be achieved only by the second metasurface, realizing the effect of beam expansion. The third metasurface is used to focus the beam.

[0033] The first metasurface can achieve beam splitting while separately controlling the object light and the reference light. For the reference light, the required phase difference can be imparted when it exits the metasurface; for the object light, off-axis focusing can be achieved when it exits the metasurface. The second metasurface can control the wavefront of the diverging object light to make the reflected beam for beam expansion perpendicular to the metasurface, thus replacing a relatively large beam expander group to achieve the beam expansion function. The third metasurface realizes the focusing of the object light. The reference beam and the object light focused by the third metasurface overlap at the same spatial position in the photosensitive medium, resulting in optical interference and thus realizing optical storage. The present invention realizes the miniaturization of the holographic storage optical system by using metasurfaces.

[0034] Thanks to the design of the first metasurface, the second metasurface and the third metasurface structures and their excellent capabilities in wavefront control, the present invention has successfully integrated the functions that traditionally require multiple mirrors to cooperate into a single mirror. In addition, a single mirror replaces a complex beam expander device, which greatly simplifies the system structure and significantly reduces its volume.

[0035] The working process of the holographic storage optical system provided by the present invention is as follows:

[0036] The writing beam is a linearly polarized light with s polarization. When this beam of light passes through the first metasurface, it will be split into two polarized lights with a constant phase difference. One of the beams of light, whose polarization direction is perpendicular to the original writing beam, is called the reference light. The reference beam is polarized along the p direction and is projected onto the photosensitive material at a specific deflection angle. This step ensures that the reference light and the subsequent object light can achieve precise interference on the photosensitive material. The other beam of light, called the object light, maintains its polarization direction as the s direction. However, through the regulation of the first metasurface, the wavefront of the object light is converted into a spherical wavefront. This conversion is crucial for subsequent off-axis focusing and the recording of holographic information. The object light achieves off-axis focusing at a specific position and continues to diverge after passing through the focus. Finally, the diverging object light reaches the second metasurface.

[0037] The second metasurface finely regulates the divergent object light wavefront. The wavefront of the object light is reshaped and reflected at a certain reflection angle. After being regulated by the second metasurface, the object light is transformed into parallel light, and the spot diameter is significantly expanded. At this time, a mask with a diameter similar to the spot diameter is placed in the optical path behind the second metasurface. Subsequently, the object light carrying the MASK information is further focused by the third metasurface. The photosensitive material is placed near the focal position of the third metasurface. Here, the object light and the reference light overlap on the photosensitive material and optical interference occurs. This interference process records the holographic information at specific spatial positions on the photosensitive material. These information exist in the form of tiny grating fringes, which carry the phase difference and amplitude information between the object light and the reference light and are the core of holographic storage technology.

[0038] In the information reading stage, a specific wavelength beam with low sensitivity is used to irradiate the position where the hologram is located. This beam is also called the probe beam. This choice of beam is to avoid unnecessary interference or damage to the photosensitive material while ensuring that the information contained in the hologram can be effectively excited. When this low-sensitivity wavelength light irradiates the hologram, a diffraction phenomenon occurs based on the microstructural characteristics of the holographic grating. These microstructures are the grating fringes formed on the photosensitive material by the interference of the object light and the reference light during the holographic information recording process. They are like tiny optical elements that have a significant impact on the propagation properties of the incident light. Specifically, when the reading light interacts with the microstructures of the holographic grating, the propagation path of the light changes, generating a specific diffraction pattern. This diffraction pattern is not randomly generated but is closely related to the information recorded in the hologram. In other words, the microstructures of the holographic grating actually act as a modulator, precisely regulating the amplitude, phase, polarization, and other properties of the reading light. It is based on this modulation effect on the reading light that the information stored in the hologram can be reproduced. When the reading light passes through the hologram, its diffraction pattern will carry the characteristics of the original information. Through appropriate detection means, these diffraction patterns can be captured, analyzed, and reconstructed to restore the original stored information content. The detection means can be selected as photodetectors, photodiodes, CMOS, etc., and the detected hologram is transmitted to the computer.

[0039] The present invention relies on the ability of the first metasurface for function integration and flexible wavefront operation to respectively add the required phases to the reference light and the object light and can refract the object light and the reference light at different deflection angles.

[0040] The second metasurface proposed by the present invention can reflect a divergent light beam from one side as parallel light to the other side. The object light passing through the second metasurface expands the beam diameter.

[0041] As a specific embodiment, the first metasurface includes a first substrate, a first sub-wavelength array, and a second sub-wavelength array; the first metasurface includes a light incident side and a light exit side; a light beam is incident from the light incident side and exits from the light exit side; the first sub-wavelength array and the second sub-wavelength array are cross-arranged on the light exit side of the first substrate.

[0042] As a specific embodiment, the materials of the first substrate, the first sub-wavelength array, and the second sub-wavelength array are all materials with a light transmittance higher than a preset light transmittance in the visible light band.

[0043] As a specific embodiment, the first sub-wavelength array is a rectangular column array with a birefringence effect or an elliptical column array with a birefringence effect; the second sub-wavelength array is a rectangular column array with a birefringence effect or an elliptical column array with a birefringence effect.

[0044] As a specific embodiment, the second metasurface includes a second substrate and a third sub-wavelength array; the third sub-wavelength array is arranged on one side of the second substrate; the material of the second substrate is a material with a reflectance higher than a preset reflectance in the visible light band. The material of the third sub-wavelength array is a material with a light transmittance higher than a preset light transmittance in the visible light band.

[0045] As a specific embodiment, the third metasurface includes a third substrate and a fourth sub-wavelength array; the fourth sub-wavelength array is arranged on one side of the third substrate; the materials of the third substrate and the fourth sub-wavelength array are both materials with a light transmittance higher than a preset light transmittance in the visible light band.

[0046] As a specific embodiment, the wavelengths of the writing light beam and the detection light beam are different. The wavelength range of the writing light beam is from the visible band to the near-infrared band.

[0047] Such as Figure 2As shown, the first metasurface includes a plurality of unit structures arranged periodically; the plurality of unit structures include a plurality of first unit structures and a plurality of second unit structures; the first unit structures and the second unit structures are arranged in a cross-distributed manner. When light passes through the first metasurface, the reference beam is deflected by the first sub-wavelength array while generating a corresponding phase difference; the object beam is deflected and focused by the second sub-wavelength array. The first metasurface is composed of a first substrate, a first sub-wavelength array, and a second sub-wavelength array, and the first sub-wavelength array and the second sub-wavelength array are cross-placed on the same side of the substrate. For example, parallel light of S polarization is incident from the side of the first metasurface where no unit structure is provided and exits from the side where the unit structure is provided, obtaining parallel light of P polarization and converging light of S polarization. The first sub-wavelength array is a plurality of first unit structures arranged periodically; the second sub-wavelength array is a plurality of second unit structures arranged periodically. Under the XYZ coordinate axes, it can be intuitively seen that the polarization directions of the parallel light of S polarization, the parallel light of P polarization, and the converging light of S polarization are different.

[0048] As Figure 3 shown, the phase and amplitude information added by the second metasurface changes the wavefront shape and propagation direction of the object beam, and the object beam transmitted through the second metasurface expands the spot diameter. The second metasurface is composed of a second substrate and a third sub-wavelength array. The third sub-wavelength array is periodically arranged on one side of the second substrate. The third sub-wavelength array includes a plurality of third unit structures; the plurality of third unit structures are arranged periodically and are arranged on one side of the second substrate. The second substrate is a high-reflection substrate. The third sub-wavelength array is a rectangular column array with birefringence effect or an elliptical column array with birefringence effect. The material of the second substrate is all a high-reflectivity material in the visible light band. Materials with high reflectivity in the visible light band include materials such as metal Au, metal Ag, metal Cu, metal Al, metal Mg, and metal Mo. After the converging light is reflected by the second metasurface, parallel light is obtained. The material of the third sub-wavelength array is a high-transmittance material in the visible light band.

[0049] As Figure 4 shown, the third metasurface is composed of a third substrate and a fourth sub-wavelength array. The fourth sub-wavelength array is periodically arranged on one side of the third substrate. Parallel light is incident from one side of the third metasurface and exits from the other side where the fourth sub-wavelength array is provided, obtaining converging light.

[0050] As a specific embodiment, the first substrate, the first sub-wavelength array, the second sub-wavelength array, the third substrate, and the fourth sub-wavelength array all adopt high-transmittance materials in the visible light band. The materials of the high-transmittance materials in the visible light band include materials such as SiO2, Ta2O5, TiO2, ITO, AZO thin film, PMMA, and PC. The first substrate and the third substrate are both transparent substrates. The first sub-wavelength array and the second sub-wavelength array are both arrays of rectangular columns or elliptical columns with birefringence effects. The fourth sub-wavelength array is a polarization-insensitive cylindrical array, an array of rectangular columns with birefringence effects, or an array of elliptical columns with birefringence effects.

[0051] As a specific embodiment, the length and width of each unit structure in the first sub-wavelength array, the second sub-wavelength array, the third sub-wavelength array, and the fourth sub-wavelength array are both smaller than the working wavelength of the holographic storage optical system.

[0052] The present invention aims to address the complexity challenges faced by current holographic storage optical systems and proposes a holographic storage optical system solution. The core of this solution lies in the ingenious utilization of the precise and efficient control ability of the metasurface over the electromagnetic properties of light waves. Based on this, a high degree of functional integration and a significant simplification of the system structure are achieved. Specifically, the present invention draws on the advanced design concept of the Huygens electromagnetic metasurface and selects dielectric artificial atoms with high transmittance and flexible phase control as the basic units for constructing the metasurface. These carefully designed unit structures not only ensure the effective transmission of light waves but also provide the possibility for realizing complex optical functions.

[0053] In the present invention, the first metasurface can not only achieve the precise beam splitting of the object light and the reference light, but also endow the reference light with a specific phase difference through the fine control of its structure, while effectively converging the object light. This design ingeniously solves the functions that require multiple optical elements to work together in traditional holographic storage systems, greatly improving the integration and efficiency of the system. Further, the present invention uses the second metasurface to replace the large-volume and complex-structured beam expander lens group in the traditional optical system, and the beam expansion function can be achieved only through the metasurface 2. This innovation not only significantly reduces the volume and weight of the system, but also reduces the manufacturing cost and maintenance difficulty, opening up a new path for the wide application of holographic storage optical systems.

[0054] In summary, the introduction of the present invention has successfully solved the problem of the complexity of the holographic storage optical system. The selected dielectric material effectively reduces energy loss due to its high transmittance characteristics, and its relatively simple processing technology provides a highly potential new method for realizing multifunctional subsurface devices and further simplifying the optical system. This innovative achievement not only promotes the development of holographic storage technology but also has a profound impact on the field of optical engineering, indicating that the future design and manufacture of optical systems will develop towards a more miniaturized, integrated, and intelligent direction.

[0055] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0056] Specific examples are used in this article to elaborate on the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A holographic storage optical system, characterized in that, The system includes: a first metasurface, a second metasurface, a third metasurface, a mask, a photosensitive material, and a photoelectric detection device; The first metasurface is disposed on the optical path of a writing beam with S polarization; the first metasurface is configured to divide the writing beam into a first polarized light with a phase difference of 90° from the polarization direction of the writing beam and a second polarized light with the same polarization direction as the writing beam and having an off-axis focusing characteristic; The second metasurface is disposed on the optical path of the second polarized light; the second metasurface is configured to reflect the second polarized light into parallel light; The mask is disposed on the optical path of the parallel light; the mask has a target image; The third metasurface is disposed on the optical path of the second polarized light; the parallel light is incident on the third metasurface after passing through the mask; the third metasurface is configured to focus the parallel light exiting from the mask; The first polarized light and the focused polarized light intersect at an intersection point, and the photosensitive material is disposed at the intersection point; On one side of the photosensitive material, a detection beam with a preset wavelength is incident on the photosensitive material from the intersection point, and the photoelectric detection device is used to receive the beam exiting from the other side opposite to the one side of the photosensitive material, so as to realize the reproduction of holographic image information.

2. The holographic storage optical system according to claim 1, wherein The first metasurface includes a first substrate, a first sub-wavelength array, and a second sub-wavelength array; the second metasurface includes a second substrate and a third sub-wavelength array; the third metasurface includes a third substrate and a fourth sub-wavelength array; The first metasurface includes a light incident side and a light exit side; the beam enters from the light incident side and exits from the light exit side; the first sub-wavelength array and the second sub-wavelength array are cross-disposed on the light exit side of the first substrate; The third sub-wavelength array is disposed on one side of the second substrate; The fourth sub-wavelength array is disposed on one side of the third substrate.

3. The holographic storage optical system according to claim 1, wherein The system further includes: a first laser and a second laser; The first laser is used to provide a writing beam with S polarization; The second laser is used to provide a detection beam with a preset wavelength.

4. The holographic storage optical system according to claim 1, wherein The photoelectric detection device includes but is not limited to a photodetector, a photodiode, and a charge-coupled device.

5. The holographic storage optical system according to claim 2, wherein, The materials of the first substrate, the first sub-wavelength array, and the second sub-wavelength array are all materials with a light transmittance higher than a preset light transmittance in the visible light band; The material of the second substrate is a material with a reflectance higher than a preset reflectance in the visible light band; The materials of the third substrate, the third sub-wavelength array, and the fourth sub-wavelength array are all materials with a light transmittance higher than a preset light transmittance in the visible light band.

6. The holographic storage optical system according to claim 1, wherein The diameter of the spot of the parallel light is larger than the diameter of the spot of the second polarized light incident on the second metasurface.

7. The holographic storage optical system according to claim 2, wherein The first sub-wavelength array, the second sub-wavelength array, and the third sub-wavelength array are all rectangular column arrays or elliptical column arrays with birefringence effects.

8. The holographic storage optical system according to claim 3, wherein The fourth sub-wavelength array is a polarization-insensitive cylindrical array, a rectangular column array with birefringence effect or an elliptical column array with birefringence effect.

9. The holographic storage optical system according to claim 1, characterized in that, The wavelength of the writing beam is different from that of the detection beam.

10. The holographic storage optical system according to claim 1, wherein, The wavelength range of the writing beam is from the visible band to the near-infrared band.

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