Hologram preparation device based on double-beam exposure

Abstract

The application discloses a hologram preparation device based on double-beam exposure, which comprises a light source, a first half-wave plate, a first polarization beam splitter, a second half-wave plate, a second polarization beam splitter, an object light branch and a first reference light branch. The light source outputs a laser beam, which is split into a first light beam and a second light beam with an included angle of 90 degrees after the polarization state is controlled by the first half-wave plate and the first polarization beam splitter. The first light beam is perpendicular to the laser beam. The second light beam is split into a third light beam and a fourth light beam with an included angle of 90 degrees after the polarization state is controlled by the second half-wave plate and the second polarization beam splitter. The third light beam is parallel to the first light beam. After the first light beam irradiates an object along the object light branch, an object light beam carrying three-dimensional light field information of the object is formed and is incident on a transmission type holographic master. The third light beam irradiates the transmission type holographic master along the first reference light branch at a preset angle θ and interferes with the object light beam to obtain a main hologram. The application improves the accuracy and efficiency of hologram preparation by integrating the optical path and exposing in stages.

Description

Technical Field

[0001] This application relates to the field of optical imaging technology, and in particular to a hologram fabrication apparatus based on dual-beam exposure. Background Technology

[0002] Denisyuk holograms, a classic holographic recording method, have long been widely used in 3D displays, anti-counterfeiting, artistic creation, and optical information storage. Their principle is based on two-beam one-step interferometry, which requires the simultaneous introduction of independent reference and object beams during recording, causing them to interfere on the surface of the recording medium to form an interference fringe structure containing information about the object's amplitude and phase. However, despite its theoretical maturity and excellent stereoscopic display effects, the actual fabrication and large-scale replication processes have revealed a series of significant technical defects and bottlenecks, severely restricting production efficiency, product consistency, and the scalability of practical applications.

[0003] Firstly, in the master recording and replication process, traditional methods rely on two independent optical path systems. During the master recording stage, a precise reference optical path and object optical path need to be matched and interfered with; while in the replication stage, another optical path needs to be constructed (including a reproduction optical branch for illuminating the master and an optical branch for contact replication). Both optical paths require the use of various optical components such as beam splitters, mirrors, spatial filters, and beam expanders. This process requires operators to perform operations such as optical path alignment, angle adjustment, and light intensity balancing. Each additional optical component introduces additional adjustment variables and potential misalignment risks, resulting in a long debugging cycle, low efficiency, and strong dependence on operator skills, hindering standardized and automated production.

[0004] Secondly, because the master recording and replication are placed in different optical path environments, errors are easily introduced. Subtle differences between the two optical paths in terms of beam incident angle, wavelength uniformity, polarization state, light field distribution, and environmental vibration isolation will be introduced and amplified during the replication process. These errors directly lead to reduced diffraction efficiency, decreased image clarity, color shift, or increased noise in the replica, making the optical quality of the replica significantly inferior to the master. Especially in applications requiring high fidelity and high-volume replication, this performance degradation caused by optical path separation becomes a key bottleneck restricting the yield and consistency of finished products.

[0005] These problems not only increase preparation costs and time, but also directly affect the final optical performance and consistency of the replicas, constituting a major obstacle to the development of this technology towards high efficiency, standardization, and industrialization. Therefore, there is an urgent need for a new approach to hologram fabrication that can simplify the optical path structure, achieve better compatibility between the master plate and the replication process, reduce manual debugging steps, and improve operational convenience and replication fidelity. Utility Model Content

[0006] To address the problems existing in the prior art, this application provides a hologram preparation device based on dual-beam exposure, which achieves stable and efficient hologram preparation through integrated optical path and staged exposure; at the same time, flexible polarization and intensity control optimizes the imaging quality.

[0007] In a first aspect, this application provides a hologram fabrication apparatus based on dual-beam exposure, comprising: A light source used to output a laser beam; The first half-wave plate is positioned behind the light source and is used to control the polarization state of the laser beam; The first polarization beam splitter includes a first incident end, a first reflecting end, and a first transmitting end; the first polarization beam splitter is disposed behind the first half-wave plate and is used to split the laser beam into a first beam and a second beam with a 90° angle, wherein the first beam is perpendicular to the laser beam. The second half-wave plate is disposed behind the first transmission end and is used to control the polarization state of the second beam. The second polarization beam splitter includes a second incident end, a second reflecting end, and a second transmitting end; the second polarization beam splitter is disposed behind the second half-wave plate and is used to split the second beam into a third beam and a fourth beam with a 90° angle, wherein the third beam is parallel to the first beam; The object-optical branch is located behind the first reflecting end and is used to transmit the first beam. The first reference beam branch is located behind the second reflecting end and is used to transmit the third beam. A transmissive holographic master is placed at the end of the object-light branch and the first reference light branch to record and reconstruct the three-dimensional light field information of the object located on the object-light branch. After the first beam illuminates the object along the object beam branch, it forms an object beam carrying the object's three-dimensional light field information and is incident on the transmissive holographic master; the third beam travels along the first reference beam branch at a preset angle. θ The main hologram is obtained by illuminating a transmissive holographic master and interfering with the beam of light from the object.

[0008] In one possible implementation of the first aspect, the object-optical branch includes a first optical switch and a first spatial filter arranged in sequence; the first optical switch is disposed behind the first reflective end and is used to turn the object-optical branch on / off.

[0009] In one possible implementation of the first aspect, the first reference optical branch includes a second optical switch, a second spatial filter, a first collimating lens, and a first dielectric mirror arranged in sequence; the first dielectric mirror is at a preset angle. θ The optical switch is tilted; the second optical switch is located behind the second reflector and is used to turn the first reference optical branch on / off.

[0010] Secondly, the hologram fabrication apparatus based on dual-beam exposure of this application further includes: The third half-wave plate is disposed behind the second transmission end and is used to control the polarization state of the fourth beam. The second reference beam branch is located behind the third half-wave plate and is used to transmit the fourth beam. An empty recording medium is placed at the end of the second reference light branch, opposite to and parallel to the completed transmissive holographic master. The third beam travels along the first reference optical branch at a preset angle. θ The back of the transmissive holographic master is illuminated to generate a reconstructed light field for the main hologram; the fourth beam, after several reflections along the second reference light branch, is positioned at a preset angle. θ When incident on an empty recording medium, it interferes with the reconstructed light field, thus achieving holographic replication.

[0011] In one possible implementation of the second aspect, the second reference light branch includes a third optical switch, a dielectric mirror group, a third spatial filter, and a second collimating lens; the third optical switch is used to turn the second reference light branch on / off; the dielectric mirror group is used to reflect the fourth beam several times, causing it to be at a preset angle. θ Incident onto an empty recording medium.

[0012] In one possible implementation, the preset angle θ Use an angle of 25~45°.

[0013] In one possible implementation, the transmissive holographic master includes a substrate layer and a recording medium layer, the recording medium layer covering and fixed to the surface of the substrate layer to form a laminated structure. Optionally, the recording medium layer is a photopolymer thin film layer.

[0014] In one possible implementation of the second aspect, the empty recording medium is fixed to the opposite side of the transmissive holographic master by a support member. Preferably, the horizontal distance between the transmissive holographic master and the empty recording medium is set to 5-20 cm.

[0015] Compared with existing technologies, this application constructs a compact optical path by combining a two-stage polarization beam splitter and a half-wave plate, reuses the first reference light branch, and employs optical switch timing control to achieve staged completion of master recording and replication within the same optical path. This reduces the number of optical components, lowers debugging difficulty, and ensures the controllability, stability, and replication consistency of hologram preparation. Specifically, this application has the following beneficial effects: 1. Once the optical path of this application has completed its initial debugging, the positions and angles of all optical components (including the medium mirror, half-wave plate, polarizing beam splitter, spatial light filter, collimating lens, recorded object, holographic recording medium, etc.) are fixed and no longer require repeated adjustments. The entire process can be completed by switching the optical switch, thereby reducing the sources of human error. The optical switch is only used for on / off control and does not change the optical path geometry. Therefore, the optical path switching itself does not introduce new debugging variables. Furthermore, after the master plate is flipped, there is no need to re-align the optical path. 2. This application integrates two optical paths into one, sharing a light source, polarization beam splitter, and first reference optical branch, thereby reducing the total number of optical components and debugging steps; it adopts a switching mode to switch the optical path function, resulting in high component reuse rate, improving the compactness of the optical path structure, and reducing costs; 3. This application employs a combination of a two-stage polarization beam splitter and a half-wave plate to achieve precise beam splitting and polarization control, while also enabling flexible adjustment of light intensity. The three half-wave plates are located at key optical path nodes and are used to precisely control the intensity ratio of the branches and adjust the polarization state of the beam. According to the embodiments, it is possible to prepare holograms with various reference light / object light intensity ratios from 1:1 to 16:1. 4. This application does not rely on closed-loop control. Its advantage lies in achieving a balance between cost and stability by simplifying the structure while ensuring performance. Compared with the existing technology that uses a closed-loop control system, this application does not introduce high costs and huge system complexity. Instead, it achieves holographic fabrication under open-loop conditions through ingenious optical architecture design, which is a more cost-effective and industrially applicable solution. 5. The optical path design can be used with various recording media according to different precision requirements, supporting the needs of high-resolution, high-diffraction-efficiency hologram preparation, and expanding the application range of holographic recording materials. Attached Figure Description

[0016] Figure 1 A schematic diagram of the optical path of a hologram fabrication apparatus based on dual-beam exposure during the master fabrication stage, provided for embodiments of this application; Figure 2 A schematic diagram of the optical path of a hologram fabrication apparatus based on dual-beam exposure during the hologram replication stage, provided for embodiments of this application; Figure 3A reconstructed image of a hologram replica provided for an embodiment of this application; Figure 4 A schematic diagram of holographic brightness in which the intensity ratio of the reference beam to the object beam is 1:1 during the master recording stage, as provided in this application embodiment; Figure 5 A schematic diagram of holographic brightness in which the intensity ratio of the reference beam to the object beam is 2:1 during the master recording stage, as provided in this application embodiment; Figure 6 A schematic diagram of holographic brightness in which the intensity ratio of the reference beam to the object beam is 4:1 during the master recording stage, as provided in this application embodiment; Figure 7 A schematic diagram of holographic brightness in which the intensity ratio of the reference beam to the object beam is 8:1 during the master recording stage, as provided in this application embodiment; Figure 8 A schematic diagram of holographic brightness in a master recording stage where the intensity ratio of the reference beam to the object beam is 12:1, provided for an embodiment of this application. Figure 9 This is a schematic diagram of the brightness of a hologram in which the intensity ratio of the reference beam to the object beam is 16:1 during the master recording stage, as provided in this application embodiment. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0018] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0019] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0020] like Figure 1 , Figure 2 As shown, a hologram fabrication apparatus based on dual-beam exposure includes a light source 1, a first half-wave plate 2, a first polarizing beam splitter 5, a second half-wave plate 3, a second polarizing beam splitter 6, an object beam branch, and a first reference beam branch. The first half-wave plate 2 is positioned behind the light source 1 to control the polarization state of the laser beam; The first polarization beam splitter 5 is disposed behind the first half-wave plate 2 and includes a first incident end, a first reflecting end 501 and a first transmitting end 502. The first incident end is used to receive the laser beam. The laser beam is split into a first beam and a second beam with an angle of 90° through the first reflecting end 501 and the first transmitting end 502. The first beam is perpendicular to the laser beam, and the second beam is consistent with the output direction of the laser beam. The second half-wave plate 3 is disposed behind the first transmission end 502 and is used to control the polarization state of the second beam. The second polarization beam splitter 6 is located behind the second half-wave plate 3 and includes a second incident end, a second reflection end 601 and a second transmission end 602. The second incident end is used to receive the second beam. The second beam is split into a third beam and a fourth beam with an angle of 90° by the second reflection end 601 and the second transmission end 602. The third beam is parallel to the first beam, and the fourth beam is in the same direction as the output of the laser beam and the second beam. The object-optical branch is located behind the first reflecting end 501 and is used to transmit the first beam. The first reference light branch is located behind the second reflector 601 and is used to transmit the third beam. Transmissive holographic master 14 is set at the end of the object-light branch and the first reference light branch to record and reconstruct the three-dimensional light field information of the object located on the object-light branch. Light source 1 outputs a laser beam. After the laser beam's polarization state is adjusted by the first half-wave plate 2, it is split into a first beam and a second beam with a 90° angle by the first polarization beam splitter 5. The first beam illuminates the object along the object light branch, undergoing diffraction / scattering to form an object beam carrying the object's three-dimensional light field information, which is then incident on the transmission holographic master 14. The second beam, after its polarization state is adjusted by the second half-wave plate 3, is further split into a third beam and a fourth beam with a 90° angle by the second polarization beam splitter 6. The third beam travels along the first reference light branch at a preset angle. θ Irradiate the transmissive holographic master 14 and interfere with the object beam to obtain the main hologram.

[0021] In one implementation, the object-optical branch includes a first optical switch 11 and a first spatial filter 19 arranged in sequence; the first optical switch 11 is located behind the first reflective end 501 and can be a shutter, used to turn the object-optical branch on / off.

[0022] In one implementation, the first reference optical branch includes a second optical switch 12, a second spatial filter 16, a first collimating lens 20, and a first dielectric mirror 10 arranged sequentially; the first dielectric mirror 10 is at a preset angle. θ The first optical switch is tilted and positioned behind the second reflector 601. It can be a shutter and is used to turn the first reference light branch on / off.

[0023] Furthermore, the hologram fabrication apparatus based on dual-beam exposure also includes a third half-wave plate 4 and a second reference light branch; The third half-wave plate 4 is disposed behind the second transmission end 602 and is used to control the polarization state of the fourth beam. The second reference beam branch is located behind the third half-wave plate 4 and is used to transmit the fourth beam. An empty recording medium 15 is provided at the end of the second reference light branch, which is opposite to and parallel to the recorded transmissive holographic master 14. The third beam travels along the first reference optical branch at a preset angle. θ The back surface of the transmissive holographic master 14 is illuminated to generate a reconstructed light field of the main hologram; the fourth beam, after several reflections along the second reference light branch, is positioned at a preset angle. θ The light is incident on the empty recording medium 15 and interferes with the reconstructed light field to achieve holographic replication.

[0024] In one implementation, the second reference light branch includes a third optical switch 13, a dielectric mirror group, a third spatial filter 18, and a second collimating lens 17; the third optical switch 13 can be a shutter, used to turn the second reference light branch on / off; the dielectric mirror group is used to reflect the fourth light beam several times, causing it to be at a preset angle. θ The light beam is incident on the empty recording medium 15. In a preferred embodiment, the medium mirror group includes a second medium mirror 7, a third medium mirror 8, and a fourth medium mirror 9, wherein the second medium mirror 7 and the third medium mirror 8 are tilted and correspondingly arranged, and the third medium mirror 8 and the fourth medium mirror 9 are tilted and correspondingly arranged. The second medium mirror 7, the third medium mirror 8, and the fourth medium mirror 9 reflect the fourth light beam three times in sequence to make it form a preset angle. θ The light is incident on the empty recording medium 15; the third spatial filter 18 and the second collimating lens 17 are arranged sequentially in the optical path between the fourth medium mirror 9 and the empty recording medium 15.

[0025] In one implementation, the preset angle θ Use an angle of 25 to 45 degrees.

[0026] In one implementation, the transmissive holographic master 14 includes a substrate layer and a recording medium layer, wherein the recording medium layer covers and is fixed to the surface of the substrate layer to form a stacked structure; the substrate layer is typically selected from glass or a similar rigid substrate, and the recording medium layer may be a photopolymer film.

[0027] In one implementation, the empty recording medium 15 is fixed to the opposite side of the transmissive holographic master 14 by a support (e.g., a plate frame); the distance between the main hologram of the transmissive holographic master 14 and the empty recording medium 15 determines the imaging depth of the reconstructed image, and the horizontal distance between the transmissive holographic master 14 and the empty recording medium 15 is set to 5 to 20 cm.

[0028] The object light branch and the first reference light branch constitute the master recording optical path, and the first reference light branch and the second reference light branch constitute the hologram replication optical path. The master recording optical path and the hologram replication constitute the two core optical path structures of this application, and the first reference light branch is a branch shared by both. Based on this optical path structure, the exposure process is divided into two stages according to the time sequence, and the working principle of the two stages is as follows.

[0029] During the master recording stage, the first optical switch 11 and the second optical switch 12 are turned on to connect the object light branch and the first reference light branch; simultaneously, the third optical switch 13 is turned off to disconnect the second reference light branch. The light source 1 outputs a laser beam. After the laser beam is polarized to S-polarization by the first half-wave plate 2, it is split into a first beam (used to generate the object beam) and a second beam (used to generate the reference beam) with a 90° angle by the first polarization beam splitter 5. The first beam enters the object light branch, is filtered by the first spatial filter 19, and then uniformly illuminates the object, forming an object beam carrying the object's three-dimensional light field information (intensity and phase). Subsequently, the object beam uniformly illuminates the recording medium layer of the transmissive holographic master 14. The second beam, after being polarized to S-polarization by the second half-wave plate 3, is reflected by the second polarization beam splitter 6 to obtain a reference beam, which enters the first reference light branch. It is then filtered by the second spatial filter 16, expanded and collimated by the first collimating lens 20, and reflected by the first medium mirror 10 at a preset angle. θ The recording medium layer of the transmissive holographic master 14 is uniformly illuminated, and interferes with the object beam from the object beam branch, forming an alternating bright and dark interference fringe structure. After exposure, ultraviolet curing and high-temperature baking are performed to fix and enhance the latent image formed by the beam interference, thus completing the recording of the master. When the master receives light again, these interference fringes can diffract light to reconstruct the original three-dimensional image of the object.

[0030] During the hologram replication stage, the horizontally flipped transmissive holographic master 14, with its recording medium layer facing the empty recording medium 15, is used to connect the first and second reference light branches. Simultaneously, the first optical switch 11 is closed to disconnect the object light branch. The light source 1 outputs a laser beam, which passes sequentially through the first half-wave plate 2, the first polarizing beam splitter 5, and the second half-wave plate 3. It is then split by the second polarizing beam splitter 6 into a third beam and a fourth beam with a 90° angle. The third beam enters the first reference light branch, is filtered by the second spatial filter 16, collimated by the first collimating lens 20, and reflected by the first medium mirror 10 at a preset angle. θ The back of the transmissive holographic master (14) is uniformly illuminated to generate a reconstructed light field of the main hologram on the transmissive holographic master; the fourth beam is adjusted to S-polarization by the third half-wave plate 4 and then enters the second reference beam branch. After being reflected several times by the dielectric mirror group, it is further filtered by the third spatial filter 18 and expanded and collimated by the second collimating lens 17 before being used as a reference beam at a preset angle. θ When incident on the left side of the empty recording medium 15, it interferes with the reconstructed light field of the aforementioned transmissive holographic master, thereby replicating the hologram.

[0031] The aforementioned exposure process employs a "dual-beam" and "two-step exposure" method. Without moving the master plate, it achieves master plate recording and hologram replication step-by-step. In each stage, a polarization beam splitter generates two laser beams as the basis for interference. Through the manipulation of several optical elements, the object beam and reference beam first intersect on the surface of the transmissive holographic master plate. Then, using the recorded master plate, the object beam is reconstructed by interfering with a parallel reference beam on the other side, thus replicating the hologram on a new recording medium. Compared to a one-step method, this application ensures optical path stability while improving operational convenience and controllability. It also allows for flexible adjustment of the intensity ratio of the two beams, thereby optimizing the brightness and imaging quality of the hologram. It should be noted that the polarization state distribution of the light incident on the polarization beam splitter can be changed by coordinating the angles of the first half-wave plate 2, the second half-wave plate 3, and the third half-wave plate 4 during the exposure process. Especially in the master plate recording stage, the intensity ratio of the two interfering beams can be arbitrarily adjusted using the first half-wave plate 2 and the second half-wave plate 3.

[0032] As mentioned earlier, the light reflected by the polarization beam splitter (corresponding to the first and third beams) is S-beam (vertically polarized light), and the light transmitted (corresponding to the second and fourth beams) is P-beam (parallel polarized light). The half-wave plate changes the projection ratio of the incident light onto the two orthogonal transmission axes of the polarization beam splitter by rotating the polarization direction of the incident light, and finally achieves the intensity distribution and control of the two outgoing beams through the polarization selection characteristics of the polarization beam splitter. If the intensity of one beam is weak, the intensity ratio of the corresponding beam can be increased by adjusting the corresponding half-wave plate, thereby ensuring sufficient intensity of the interference beam. It should be noted that once the angle of the half-wave plate is determined in the early stage of optical path construction, it will not be adjusted later. Thus, the intensity ratio of the three beams—object beam branch, first reference beam branch, and second reference beam branch—is controlled by the first half-wave plate 2, the second half-wave plate 3, the first polarization beam splitter 5, and the second polarization beam splitter 6. The third half-wave plate 4 is used to convert all the P-beams transmitted from the second polarization beam splitter 6 into S-beams to ensure that the polarization state of the light in the second reference beam branch is S-beam.

[0033] The feasibility and effectiveness of this application are verified below with reference to an embodiment.

[0034] In this embodiment, to enhance the brightness of the reflective Denisyuk hologram, a 639nm single-mode solid-state laser is used as the light source 1, and the object is a "cat," positioned on the object-beam branch. It should be noted that modern single-mode solid-state lasers (such as the 639nm laser used in this embodiment) can achieve output power of 500mW or even higher, for example, models such as Changchun New Industries MSL-DU-639-W and MSL-R-639. Even after processes such as polarization beam splitting, half-wave plate attenuation, and medium mirror reflection, the light intensity reaching the recording medium is still far higher than the threshold required for holographic recording (typically on the order of mW / cm²). In this embodiment, the exposure intensity is 3mW / cm², which meets the basic requirements for interference recording.

[0035] First, a transmissive holographic master 14 of the object "cat" is prepared. The exposure path of the master is as follows: Figure 1As shown: The first polarization beam splitter 5 splits the laser into two beams at a 90-degree angle. One beam is reflected by the second polarization beam splitter 6 and remains parallel to the other beam. After filtering and collimation, the two beams form a parallel beam with a diameter of 90 mm. The left beam uniformly illuminates the recorded object "cat," forming an object beam carrying the three-dimensional light field information of the "cat," which then illuminates the photopolymer film on the surface of the transmissive holographic master. At the same time, the other parallel beam, reflected by the first dielectric mirror 10, serves as a reference beam, uniformly illuminating the photopolymer film at a 32° angle and interfering with the object beam. After subsequent ultraviolet curing and high-temperature baking, the holographic recording of the master hologram "cat" is finally completed. The entire process controls the exposure intensity at 3 mW / cm² and the exposure dose at 200 mJ / cm². Post-processing includes 4 minutes of dark reaction, 8 minutes of ultraviolet curing, and 10 minutes of baking at 110°C.

[0036] Figure 2 The replication path for the completed master hologram is shown: First, the transmissive holographic master 14 carrying the master hologram is horizontally flipped and then fixed to the [location / location]. Figure 1 At the same location; subsequently, the beam from the first reference light branch, after reflection, illuminates the master hologram at the same angle of 32°, reconstructing the three-dimensional light field information of the object "cat," as shown below. Figure 3 As shown, a blank photopolymer film is fixed on a plate frame 2 cm to the left of the master hologram, with the two kept parallel. In the second reference light branch, the beam undergoes three reflections, filtering, expansion, and collimation, before illuminating the left side of the blank photopolymer film, where it interferes with the reconstructed light field generated by the master hologram.

[0037] like Figures 4-9 As shown, this embodiment recorded the brightness of the master hologram under six intensity ratio conditions. It can be observed that when the intensities of the reference beam and the object beam are similar, the hologram brightness is highest, but the difference is negligible. When the intensity of the reference beam increases to four times that of the object beam, the hologram brightness decreases significantly. Furthermore, as the intensity of the reference beam continues to increase while the intensity of the object beam remains relatively weak, the hologram brightness decreases rapidly. When the intensity ratio of the reference beam to the object beam reaches 16:1, its brightness is close to that of a hologram prepared in a one-step method. Based on this, this application ensures consistent optical conditions throughout the entire exposure process (recording and replication stages), ensuring uniform, high-definition, and repeatable hologram quality, thereby overcoming problems such as decreased diffraction efficiency and sharpness of the replica caused by operating recording and replication in different optical paths.

Claims

1. A hologram fabrication apparatus based on dual-beam exposure, characterized in that, include: Light source (1), used to output laser beam; The first half-wave plate (2) is disposed behind the light source (1) and is used to control the polarization state of the laser beam; The first polarization beam splitter (5) includes a first incident end, a first reflecting end (501) and a first transmitting end (502); the first polarization beam splitter (5) is disposed behind the first half-wave plate (2) and is used to split the laser beam into a first beam and a second beam with a 90° angle between them, wherein the first beam is perpendicular to the laser beam. The second half-wave plate (3) is disposed behind the first transmission end (502) and is used to control the polarization state of the second beam. The second polarization beam splitter (6) includes a second incident end, a second reflection end (601) and a second transmission end (602); the second polarization beam splitter (6) is disposed behind the second half-wave plate (3) and is used to split the second beam into a third beam and a fourth beam with an angle of 90°, wherein the third beam is parallel to the first beam; The object-optical branch is located behind the first reflecting end (501) and is used to transmit the first beam. The first reference light branch is located behind the second reflecting end (601) and is used to transmit the third beam. Transmissive holographic master (14) is set at the end of the object light branch and the first reference light branch to record and reconstruct the three-dimensional light field information of the object located on the object light branch; After the first beam illuminates the object along the object beam branch, it forms an object beam carrying the object's three-dimensional light field information and is incident on the transmissive holographic master (14); the third beam travels along the first reference beam branch at a preset angle. θ Irradiate the transmissive holographic master (14) and interfere with the object beam to obtain the master hologram.

2. The hologram fabrication apparatus based on dual-beam exposure according to claim 1, characterized in that, The object-optical branch includes a first optical switch (11) and a first spatial filter (19) arranged in sequence; the first optical switch (11) is located behind the first reflective end (501) and is used to turn the object-optical branch on / off.

3. The hologram fabrication apparatus based on dual-beam exposure according to claim 1, characterized in that, The first reference light branch includes a second optical switch (12), a second spatial filter (16), a first collimating lens (20), and a first dielectric mirror (10) arranged in sequence; the first dielectric mirror (10) is at a preset angle. θ The first optical switch (12) is positioned at an angle and is located behind the second reflector (601) to turn the first reference optical branch on / off.

4. The hologram fabrication apparatus based on dual-beam exposure according to claim 1, characterized in that, Also includes: The third half-wave plate (4) is disposed behind the second transmission end (602) and is used to control the polarization state of the fourth beam. The second reference beam branch is located behind the third half-wave plate (4) and is used to transmit the fourth beam. An empty recording medium (15) is placed at the end of the second reference light branch, opposite to and parallel to the recorded transmissive holographic master (14); The third beam travels along the first reference optical branch at a preset angle. θ The back of the transmissive holographic master (14) is illuminated to generate the reconstructed light field of the main hologram; the fourth beam is reflected several times along the second reference light branch and then at a preset angle. θ The light is incident on the empty recording medium (15) and interferes with the reconstructed light field to achieve holographic replication.

5. The hologram fabrication apparatus based on dual-beam exposure according to claim 4, characterized in that, The second reference light branch includes a third optical switch (13), a dielectric mirror group, a third spatial filter (18), and a second collimating lens (17); the third optical switch (13) is used to turn the second reference light branch on / off; the dielectric mirror group is used to reflect the fourth beam several times, so that it is at a preset angle. θ Incident onto an empty recording medium (15).

6. The hologram fabrication apparatus based on dual-beam exposure according to claim 1, characterized in that, The preset angle θ Use an angle of 25 to 45 degrees.

7. The hologram fabrication apparatus based on dual-beam exposure according to claim 1, characterized in that, The transmissive holographic master includes a base layer and a recording medium layer, with the recording medium layer covering and fixed to the surface of the base layer to form a stacked structure.

8. The hologram fabrication apparatus based on dual-beam exposure according to claim 7, characterized in that, The recording medium layer is a photopolymer thin film layer.

9. The hologram fabrication apparatus based on dual-beam exposure according to claim 4, characterized in that, The empty recording medium (15) is fixed to the opposite side of the transmissive holographic master (14) by a support member.

10. The hologram fabrication apparatus based on dual-beam exposure according to claim 4, characterized in that, The horizontal distance between the transmissive holographic master (14) and the empty recording medium (15) is set to 5 ~ 20 cm.

Images