Method and device for processing birefringent anisotropic structure
By utilizing the focus offset and processing sequence of the first and second laser beams on the substrate, combined with the birefringent anisotropic structure generated by the same source laser, the problem of slow device response speed in the prior art is solved, and fast writing and high-speed writing of multidimensional optical storage are realized.
Patent Information
- Application Number
- CN202511263075.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-05
- Publication Date
- 2025-11-07
AI Technical Summary
The fabrication process of birefringent nanograting structures in the prior art relies on polarization modulation and multi-pulse processes, which results in slow device response speed and makes it difficult to achieve high-speed writing.
A birefringent anisotropic structure is formed on a substrate using first and second laser beams with specific focus offsets and processing sequences. Two laser beams are generated from the same source to reduce errors and control time delay and energy ratio, thereby reducing the number of pulses.
It enables fast writing without polarization modulation, improving the forming speed of birefringent anisotropic structures and the writing speed of multidimensional optical storage.
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Figure CN120901467A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of laser processing, in particular to a processing method and device of birefringence anisotropic structure. BACKGROUND
[0002] With the rapid development of digitalization and artificial intelligence, data is growing explosively. For example, personal data stored in mobile phones and computers, access data stored by enterprises and governments, and traffic data generated by traffic operation, etc. These data need to be stored in storage media, such as traditional electromagnetic storage media, solid state hard disks, mechanical hard disks, etc. The service life of such traditional storage media is usually 5-10 years, and the storage capacity per unit area is limited, which cannot meet the storage needs of the future explosive growth of data.
[0003] Researchers in the prior art have developed a new storage technology that uses femtosecond laser to store information inside quartz materials. By focusing femtosecond laser inside quartz substrate, hundreds of layers of data can be stored.
[0004] The implementation of the above storage structure mainly depends on the birefringent nanograting structure processed on the quartz glass. The birefringent nanograting structure is periodically arranged by two layers with different refractive indexes along the polarization direction of incident light, and has good thermal stability, periodicity and repeatable erasing, so it can be used for five-dimensional data storage.
[0005] Among them, the birefringent nanograting shows uniaxial birefringence characteristics, which is the basic basis for judging whether the birefringent nanograting structure is generated in the focusing area after the quartz glass is irradiated by the ultra-short pulse laser. The observation method of the birefringent nanograting structure is usually to use birefringence microscope to image the birefringence of the processing area. The nanograting structure has a certain delay value and a consistent slow axis angle.
[0006] The prior art uses birefringent nanograting structure for optical data storage, mainly by controlling the polarization direction and pulse intensity to realize independent control of the slow axis angle and optical path delay of the birefringent nanograting structure. It mainly relies on the polarization transformation of incident light and the control of pulse intensity in the writing process.
[0007] In the above preparation process, a half-wave plate or an electro-optic modulator is usually needed to realize it, but such devices have a slow response speed to high-power femtosecond laser, making it difficult to write at high speed, and the above process also needs to go through a multi-pulse action process. For details, refer to Figure 1 It takes 20 pulses to generate anisotropic structure, resulting in a long structure generation time, which further restricts the writing speed. SUMMARY
[0008] In view of the technical problems of slow device response speed and large number of required pulses in the prior art birefringent nanograting structure preparation mainly relying on polarization modulation and multi-pulse process, the application provides a birefringent anisotropic structure processing method, which has the advantages of no polarization modulation and small number of pulses, and thus realizes the purpose of fast writing, thereby having the advantage of high-speed multi-dimensional optical storage.
[0009] In a first aspect, the application provides a birefringent anisotropic structure processing method, comprising:
[0010] A first laser beam is focused on a substrate with a first processing focal point to process a micro-hole structure;
[0011] A second laser beam is further processed on the micro-hole structure with a second processing focal point to form a birefringent anisotropic structure;
[0012] The second processing focal point is laterally offset and Z-directionally offset relative to the first processing focal point, wherein the lateral offset value includes 0.3um-0.5um, and the Z-directional offset value includes 7um-9um.
[0013] Specifically, the main technical idea of the application is to process the substrate with the first laser beam and the second laser beam which are offset and have a processing sequence to form a birefringent anisotropic structure. Since the processing of the birefringent anisotropic structure does not require polarization support, the number of pulses in the processing process can be effectively reduced, and the processing complexity can be reduced, so that the birefringent anisotropic structure has a faster response speed and a shorter processing time, thereby improving the forming speed of the birefringent anisotropic structure, and achieving the purpose of high-speed writing of multi-dimensional optical storage.
[0014] Further, the first processing focal point is focused within 250um-300um of the surface of the substrate.
[0015] Further, the energy pulse value of the first laser beam and the second laser beam both includes 600nJ-900nJ.
[0016] Optionally, the first laser beam and the second laser beam are generated by splitting a laser source;
[0017] The second laser beam has a preset processing time delay relative to the first laser beam, and the processing time delay value includes 1ps-1ns.
[0018] Optionally, another technical idea of the application is to generate the first laser beam and the second laser beam with homologous laser, which can reduce the error caused by selecting different laser sources, and can also effectively control the processing time delay and energy ratio of the two, thereby simplifying the processing method provided by the application.
[0019] In a second aspect, the present application provides a birefringent anisotropic structure processing device, which comprises a first adjusting unit, a second adjusting unit and a processing unit.
[0020] The first laser beam is adjusted by the first adjusting unit and then enters the processing unit to focus on the substrate by the first processing focal point to process a micro-hole structure.
[0021] The second laser beam is adjusted by the second adjusting unit and then enters the processing unit to further process the micro-hole structure by the second processing focal point to form a birefringent anisotropic structure.
[0022] The second processing focal point is laterally offset and Z-directionally offset relative to the first processing focal point.
[0023] Specifically, the present application provides a birefringent anisotropic structure processing device based on any possible implementation of the first aspect, and the technical effects provided by the present application can be understood with reference to the technical effects provided by any embodiment of the first aspect.
[0024] Further, the processing device further comprises a laser and a first beam splitter arranged on the exit path of the laser.
[0025] The first beam splitter is used to split the laser beam generated by the laser into the first laser beam and the second laser beam according to a preset ratio.
[0026] Further, the laser beam is reflected by the first beam splitter to generate the first laser beam, and is transmitted synchronously to generate the second laser beam.
[0027] The first laser beam is reflected by the first mirror of the first adjusting unit and the second beam splitter of the processing unit in sequence and then enters the objective lens of the processing unit.
[0028] The second laser beam passes through the delay device, the focusing lens and the galvanometer of the second adjusting unit, and then enters the objective lens via the reflection of the galvanometer and the transmission of the second beam splitter.
[0029] The delay device is used to generate a processing time delay, the focusing lens is used to generate a Z-directional offset, and the galvanometer is used to generate a lateral offset.
[0030] Optionally, the laser beam is transmitted by the first beam splitter to generate the first laser beam, and is reflected synchronously to generate the second laser beam.
[0031] The first laser beam is reflected by the first mirror of the first adjusting unit and then transmitted by the second beam splitter of the processing unit in sequence, and then enters the objective lens of the processing unit.
[0032] The second laser beam passes through the time delay unit, the focusing lens, the second mirror and the acousto-optic modulator of the second adjusting unit, and enters the objective lens via reflection of the second mirror and the second beam splitter;
[0033] The acousto-optic modulator is used to generate lateral shift.
[0034] In a third aspect, the application provides a multi-dimensional data storage medium prepared by the processing method of the birefringent anisotropic structure according to any possible embodiment of the first aspect, so as to realize fast data writing through the multi-dimensional data storage medium, and data reading through the birefringent microscope.
[0035] In summary, the processing method of the birefringent anisotropic structure has at least the following advantages:
[0036] 1. The first laser beam and the second laser beam with shift and processing sequence are used to process the substrate to form the birefringent anisotropic structure. Since the processing of the birefringent anisotropic structure does not need polarization modulation, the number of pulses in the processing process is effectively reduced, and the processing complexity is reduced, so that the response speed is faster and the processing time is shorter, thereby improving the forming speed of the birefringent anisotropic structure, and achieving the purpose of high-speed writing of multi-dimensional optical storage.
[0037] 2. The first laser beam and the second laser beam are generated by using homologous laser, which reduces the error caused by selecting different laser sources, and effectively controls the processing time delay and energy ratio of the two, thereby simplifying the processing method. BRIEF DESCRIPTION OF DRAWINGS
[0038] The application will be described in further detail below with reference to the drawings and preferred embodiments, but those skilled in the art will appreciate that the drawings are only drawn for the purpose of explaining the preferred embodiments and therefore should not be regarded as limiting the scope of the application. In addition, unless specifically indicated, the drawings only schematically represent the composition or structure of the described objects and can include exaggerated display, and the drawings are not necessarily drawn to scale.
[0039] Figure 1 It is a schematic diagram of in-situ multi-pulse processing anisotropic structure in the prior art;
[0040] Figure 2 It is a flowchart of a processing method of a birefringent anisotropic structure according to an embodiment of the application;
[0041] Figure 3A flow chart of a processing method of a birefringent anisotropic structure according to another embodiment of the present application;
[0042] Figure 4 A processing schematic diagram of a substrate according to an embodiment of the present application;
[0043] Figure 5 A lateral offset schematic diagram of a lateral offset according to an embodiment of the present application;
[0044] Figure 6 A processing result when a second processing focal point is at different lateral displacement relative to a first processing focal point according to the present application.
[0045] Figure 7 A processing result when a second processing focal point is at different Z-direction displacement relative to a first processing focal point according to the present application.
[0046] Figure 8 A composition schematic diagram of a processing device of a birefringent anisotropic structure according to an embodiment of the present application;
[0047] Figure 9 A composition schematic diagram of a processing device of a birefringent anisotropic structure according to another embodiment of the present application;
[0048] Figure 10 A schematic diagram of a terminal according to an embodiment of the present application;
[0049] Figure 11 An experimental diagram of a micro-hole structure processed by a first laser beam according to an embodiment of the present application;
[0050] Figure 12 An experimental verification diagram of a birefringent anisotropic structure further processed by a second laser beam according to an embodiment of the present application. DETAILED DESCRIPTION
[0051] The present application will be described in detail below with reference to the accompanying drawings and embodiments. Figures 2 to 12 The present application will be described in detail below with reference to the accompanying drawings and embodiments.
[0052] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.
[0053] The present application utilizes the processing of a first laser beam combined with a focal point offset and a time-delayed second laser beam, and realizes the generation of a birefringent anisotropic structure without laser polarization modulation and with fewer pulse numbers, thereby achieving the purpose of accelerating the direct writing efficiency of multi-dimensional storage.
[0054] Embodiment 1:
[0055] Please refer to Figure 2 , Figure 2 A flowchart of a processing method of a birefringent anisotropic structure according to an embodiment of the present application is shown. Based on the flowchart shown in FIG. 1, the working principle of the present application is as follows: first, a first laser beam is used to focus at a first processing focal point on a substrate to process a micro-hole structure, and then a second laser beam is used to further process the micro-hole structure to form a birefringent anisotropic structure. The second processing focal point of the second laser beam is laterally offset and Z-directionally offset compared with the first processing focal point of the first laser beam, and the second laser beam lags behind the first laser beam in processing, i.e., after the micro-hole structure is processed, the birefringent anisotropic structure is generated based on the further processing of the micro-hole structure. Figure 2
[0056] It is worth explaining that the lateral offset occurs in the direction perpendicular to the laser incidence direction (parallel to the substrate surface), and the Z-directional offset occurs in the direction parallel to the laser incidence direction (or perpendicular to the substrate surface).
[0057] Embodiment 2:
[0058] Further, please refer to Figure 3 , Figure 3 A flowchart of a processing method of a birefringent anisotropic structure according to another embodiment of the present application is shown.
[0059] Based on the embodiment 1, the first laser beam and the second laser beam are homologous lasers, which are generated by a laser source to split into the first laser beam and the second laser beam, and the processing procedures of the first laser beam and the second laser beam are still performed according to the embodiment 1, so as to realize the processing of the birefringent anisotropic structure.
[0060] Since the first laser beam and the second laser beam are homologous, there is no device difference between them, and the processing consistency and reliability are better. It is worth understanding that the first laser beam and the second laser beam can also be generated by two lasers of the same frequency respectively, but compared with the homologous laser, the device volume is larger and there is an additional same frequency device.
[0061] Optionally, the value of the processing delay includes 1 ps to 1 ns.
[0062] In theory, the smaller the processing delay is, the better it is, but on the one hand, it is limited by the delay accuracy of the delay device, and on the other hand, it is also limited by the forming time of the micro-hole structure. Therefore, without considering the delay accuracy of the delay device, the longest forming time of the micro-hole structure is the optimal value of the processing delay, which can effectively improve the direct writing rate of the processing method provided by the present application.
[0063] Optionally, the laser is a femtosecond direct writing laser.
[0064] It is worth explaining that femtosecond laser direct writing is a technology for micro-nano machining by using the ultrafast pulse and ultrastrong transient energy of femtosecond laser. It has the processing precision of super-diffraction limit, rich processable materials, nonlinear multi-photon absorption and other excellent characteristics, which makes it have unique advantages in three-dimensional micro-nano manufacturing and can meet the processing needs of micro-optical elements and three-dimensional systems with complex surface profile and nanoscale surface roughness.
[0065] Optionally, the energy pulse values of the first laser beam and the second laser beam both include 600nJ-900nJ.
[0066] According to multiple experimental verifications, the first laser beam needs to be maintained between 600nJ-900nJ to form a micro-hole structure, and the second laser beam also needs to be maintained between 600nJ-900nJ to further process the micro-hole structure into a birefringent anisotropic structure. In theory, all possible combinations of the energy pulse of the first laser beam and the second laser beam between 600nJ-900nJ can achieve the generation of the birefringent anisotropic structure. Another factor affecting the processing pulse energy is the objective NA value. When a higher NA objective is used for processing, it can be predicted that the required pulse energy is lower.
[0067] Embodiment 3
[0068] Based on Embodiment 1 or Embodiment 2, please refer to Figure 4 , Figure 4 The processing schematic diagram of the substrate provided by an embodiment of the present application. In Figure 4 The left side of the arrow is a processing schematic of the micro-hole structure. The first processing focal point of the first laser beam is focused inside Ya on the front surface of the substrate.
[0069] Exemplarily, 250um≤Ya≤300um, and a preset energy pulse of 600nJ-900nJ is processed for a preset time to form a series of micro-hole structures (left side of the connected circular holes). Figure 3
[0070] It should be noted that the value range of Ya is not a necessary condition for generating a birefringent anisotropic structure, so the value range of Ya is not limited in this application. It can be shallower than the above value, or it can be further deepened.
[0071] After the first laser beam completes the processing of a series of micro-hole structures, the second laser beam is used to further process the series of micro-hole structures. See Figure 4 Right side, (a) is the first machining focal point of the second laser beam located on the left of the series of micro-hole structures, and (b) is the second machining focal point of the second laser beam located on the right of the series of micro-hole structures, that is, as long as the second machining focal point is located anywhere in the series of micro-hole structures, as long as the lateral offset is 0.3um-0.5um and the Z-direction offset is 7um-9um, the birefringence anisotropic structure can be machined. The distance between the two longitudinal dashed lines in (b) is the lateral offset distance, and the distance between the two axial dashed lines is the Z-direction offset distance.
[0072] For further explanation of the offset schematic of the lateral offset, please refer to Figure 5 , Figure 5 The offset schematic of the lateral offset provided by an embodiment of the present application. Figure 5 In the embodiment, the corresponding coordinate system is established based on the substrate plane with x and y, and the second machining focal point of the second laser beam can be diverged along the annular range.
[0073] For further explanation of the offset schematic of the lateral offset, please refer to Figure 6 , Figure 6 The machining results of the second machining focal point relative to the first machining focal point at different lateral displacements can be found that the birefringence anisotropic structure can be generated when the lateral offset is within 0.3um-0.5um, and the birefringence anisotropic structure cannot be generated at other positions.
[0074] For further explanation of the offset schematic of the lateral offset, please refer to Figure 7 , Figure 7 The machining results of the second machining focal point relative to the first machining focal point at different Z-direction displacements can be found that the birefringence anisotropic structure can be generated when the Z-direction offset is within 7um-9um, and the birefringence anisotropic structure cannot be generated at other positions.
[0075] That is, the birefringence anisotropic structure can be formed when the lateral offset is within 0.3um-0.5um and the Z-direction offset is within 7um-9um.
[0076] Optionally, the material of the substrate is quartz.
[0077] Embodiment 4:
[0078] Based on any possible embodiment in Embodiments 1-3, please refer to Figure 8 , Figure 8 The composition schematic diagram of a machining device of a birefringence anisotropic structure provided by an embodiment of the present application.
[0079] In Figure 8The components of the processing apparatus are shown in dashed boxes. It includes a laser source, a first adjustment unit, a second adjustment unit, and a processing unit. The laser source generates a first laser beam and a second laser beam. The first adjustment unit adjusts the first laser beam to enter the processing unit and focuses it on the substrate at a first processing focus to process a microporous structure. The second adjustment unit adjusts the second laser beam to enter the processing unit and further processes the microporous structure at a second processing focus to form a birefringent anisotropic structure. The processing unit is used to focus within the substrate to process the substrate.
[0080] Furthermore, Figure 8 The laser source includes a laser and a first beam splitter. The laser is split into two beams, a first laser beam and a second laser beam, by the first beam splitter. The preset ratio ensures that the energy pulses of both the first and second laser beams are within the range of 600nJ-900nJ, for example, 5:5, 4:6, 6:4, etc. Regardless of the preset ratio used for energy pulse distribution, the energy pulses of both the first and second laser beams should remain within the 600nJ-900nJ range.
[0081] Optionally, the first beam splitter can be either a beam splitter or a polarizing beam splitter. It is worth noting that if the first and second laser beams are generated by two lasers, then the laser source includes the first and second lasers and a frequency coordinator connecting them.
[0082] Figure 9 The first adjustment unit includes only the first reflector. Since the first laser beam is generated by reflection from the first beam splitter, it only needs to adjust its path through the first reflector to enter the second beam splitter and be reflected into the objective lens to process the substrate under the objective lens.
[0083] The second adjustment unit includes a delay unit, a focusing lens, and a galvanometer. The delay unit generates a processing delay, the focusing lens generates a Z-axis offset, and the galvanometer generates a lateral offset. Therefore, the second laser beam can have its preset delay controlled by the delay unit, causing it to lag behind the processing of the first laser beam. The focusing lens and galvanometer can adjust the offset of the second focal length of the second laser beam, thereby achieving a lateral and Z-axis offset of the second processing focus relative to the first processing focus.
[0084] It is worth explaining that the order in which the delay unit, focusing lens, and galvanometer are arranged is not required. All three are functional devices, and they only need to perform their respective functions to realize the processing method provided by this invention. For example, whether the delay unit is located after the galvanometer, or after the focusing lens, or after the focusing lens, it does not affect the adjustment function of the second adjustment unit.
[0085] Therefore, based on Figure 9As can be seen, the working principle of the present invention is as follows: first, a common source laser is generated by a laser. After the common source laser is emitted to the first beam splitter, it is reflected to form a first laser beam and transmitted to form a second laser beam. Due to the setting of the delay device in the second adjustment unit, the first laser beam will first enter the objective lens through the reflection of the first reflecting mirror and the second beam splitter, thereby processing the substrate surface within 250um-300um with the first processing focus to form a series of microporous structures.
[0086] After being adjusted by the delay unit, focusing lens, and galvanometer, the second laser beam's second processing focus is shifted laterally and in the Z-axis compared to the first processing focus of the first laser, thus resulting in a shifted laser spot (refer to...). Figure 4 , Figure 5 The microporous structure is further processed to form a birefringent anisotropic structure.
[0087] It is worth noting that the processing method of the present invention can also be achieved by either forming the first laser beam through transmission via the first beam splitter or forming the second laser beam through reflection via the first beam splitter. Further explanation is not provided here, but please refer to the following figures. Figure 9 They can be mutually verified.
[0088] Example 5:
[0089] In any of the possible implementations of Examples 1 to 3, please refer to Figure 9 , Figure 9 This is a schematic diagram of the composition of a processing apparatus for a birefringent anisotropic structure provided in another embodiment of the present invention.
[0090] Unlike Figure 8 As shown, Figure 9 The first laser beam is generated through transmission and enters the objective lens through reflection by the first reflecting mirror and transmission by the second beam splitter, thereby realizing the fabrication of the micro-hole structure. The second laser beam is generated through reflection, passes through a delay unit, a second reflecting mirror, a focusing lens, and an acousto-optic modulator, and enters the objective lens through reflection by the second beam splitter, thereby further processing the micro-hole structure to form a birefringent anisotropic structure. In comparison, Figure 9 Lateral offset is generated using an acousto-optic modulator, without the need for a galvanometer.
[0091] In Examples 5 and 6, the NA of the objective lens was 0.55.
[0092] Optionally, the delay device can be a high-refractive-index crystal.
[0093] based on Figure 8 and Figure 9The processing device of the present application can effectively improve the direct writing speed of multi-dimensional optical storage without complex polarization control and multi-pulse evolution compared with conventional polarization processing. In addition, the processing difficulty of the birefringent anisotropic structure is greatly reduced, and the processing reliability and processing speed are effectively improved by using only basic optical devices such as beam splitters, mirrors, focusing lenses, delay timers, galvanometer mirrors or acousto-optic modulators in the embodiments provided by the present application.
[0094] Embodiment 6:
[0095] In any possible implementation manner of the embodiments 1 to 5, please refer to Figure 10 , Figure 10 An architecture schematic diagram of a terminal provided by an embodiment of the present application is provided. The terminal includes a communication unit, a processing unit and a storage unit, and a bus for connecting the above-mentioned units. The storage unit stores a processing method of a birefringent anisotropic structure, which can be called by the processing unit to control the processing device of the birefringent anisotropic structure provided by the present application, so as to realize the processing of the birefringent anisotropic structure. The communication unit is used for the interaction between the terminal and other devices.
[0096] Further, in order to explain the technical effects of the processing method, the processing device, the terminal and the medium provided by the present application, please refer to Figure 11 , Figure 11 An experimental diagram of a micropore structure processed by a first laser beam provided by an embodiment of the present application is provided. Figure 11 A series of micropore structures can be obviously observed in the substrate. Meanwhile, in combination with Figure 12 , Figure 12 An experimental verification diagram of a birefringent anisotropic structure further processed by a second laser beam provided by an embodiment of the present application is provided. Based on Figure 12 (comparison Figure 5 ), it can be known that the processing method and the processing device provided by the present application can process the birefringent anisotropic structure in any direction of the micropore structure.
[0097] In an embodiment, a computer device is provided, including a memory and a processor, and the memory stores a computer program. When the processor executes the computer program, the steps in the above-mentioned processing method embodiment of the birefringent anisotropic structure are realized.
[0098] In an embodiment, a computer readable storage medium is provided, and the computer readable storage medium stores a computer program. When the computer program is executed by a processor, the steps in the above-mentioned processing method embodiment of the birefringent anisotropic structure are realized.
[0099] In one embodiment, a computer program product is provided, comprising a computer program which, when executed by a processor, implements the steps of one of the above-mentioned embodiments of a method of processing a birefringent anisotropic structure.
[0100] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by a computer program instructing related hardware, and the computer program can be stored in a non-volatile computer readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments of each method.
[0101] The technical features of the above embodiments can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as falling within the scope of the present disclosure.
[0102] The above has described the present application in detail, and the principle and implementation of the present application have been described by applying specific examples. The above embodiment is only used to help understand the present application and the core idea. It should be pointed out that for ordinary skilled in the art, without departing from the principle of the present application, the present application can be improved and modified in several ways, and these improvements and modifications also fall within the protection scope of the claims of the present application.
Claims
1. A method of processing a birefringent anisotropic structure, characterized in that, The application relates to a birefringence anisotropy structure processing method and device. A first laser beam focuses on a substrate with a first processing focus point to process a micro-hole structure; A second laser beam further processes the micro-hole structure with a second processing focus point to form the birefringence anisotropy structure; The second processing focus point is laterally offset and Z-directionally offset relative to the first processing focus point, wherein the lateral offset is 0.3-0.5 um, and the Z-directional offset is 7-9 um.
2. A method of processing a birefringent anisotropic structure according to claim 1, wherein The first processing focus point is focused on the surface of the substrate within 250-300 um.
3. A method of processing a birefringent anisotropic structure according to claim 1 or 2, characterized in that, The energy pulse of the first laser beam and the second laser beam is 600-900 nJ.
4. The method of claim 1, wherein the birefringent anisotropic structure is formed by a process selected from the group consisting of: ion exchange, ion implantation, and ion irradiation. The first laser beam and the second laser beam are generated by beam splitting of a laser source; The second laser beam has a preset processing time delay relative to the first laser beam, and the processing time delay is 1 ps-1 ns.
5. An apparatus for processing a birefringent anisotropic structure for implementing a method for processing a birefringent anisotropic structure according to any one of claims 1 to 4, characterized in that, The processing device comprises a first adjusting unit, a second adjusting unit and a processing unit; The first laser beam is adjusted by the first adjusting unit and then enters the processing unit to focus on the substrate with the first processing focus point to process a micro-hole structure; The second laser beam is adjusted by the second adjusting unit and then enters the processing unit to further process the micro-hole structure with the second processing focus point to form the birefringence anisotropy structure; The second processing focus point is laterally offset and Z-directionally offset relative to the first processing focus point.
6. An apparatus for processing a birefringent anisotropic structure as claimed in claim 5, characterized in that The processing device further comprises a laser and a first beam splitter mirror arranged on the exit path of the laser; The first beam splitter mirror is used to split the laser beam generated by the laser into the first laser beam and the second laser beam according to a preset ratio.
7. An apparatus for processing a birefringent anisotropic structure as claimed in claim 6, characterized in that The laser beam is reflected by the first beam splitter mirror to generate the first laser beam and is synchronously transmitted to generate the second laser beam; The first laser beam is reflected by a first mirror of the first adjusting unit and a second beam splitter mirror of the processing unit in sequence and then enters an objective lens of the processing unit; The second laser beam passes through a time delay device, a focusing lens and a galvanometer of the second adjusting unit and then enters the objective lens through reflection of the galvanometer and transmission of the second beam splitter mirror; The time delay device is used to generate the processing time delay, the focusing lens is used to generate the Z-directional offset, and the galvanometer is used to generate the lateral offset.
8. The apparatus of claim 6, wherein the apparatus is configured to process the birefringent anisotropic structure by: The laser beam is transmitted by the first beam splitter mirror to generate the first laser beam and is synchronously reflected to generate the second laser beam; The first laser beam is reflected by a first mirror of the first adjusting unit and transmitted by a second beam splitter mirror of the processing unit in sequence and then enters an objective lens of the processing unit; The second laser beam passes through a time delay device, a focusing lens, a second mirror and an acousto-optic modulator of the second adjusting unit and then enters the objective lens through reflection of the second mirror and the second beam splitter mirror; The acousto-optic modulator is used to generate the lateral offset.
9. A multi-dimensional data storage medium, characterized by The birefringence anisotropy structure is prepared by the processing method.