V-shaped trend volume grating batch exposure device and exposure control method

Abstract

The invention discloses a V-shaped trend volume grating batch exposure device and an exposure control method. The exposure device comprises a light source, a beam splitter, a first reflecting mirror, a second reflecting mirror, a transmission device and an objective table, the transmission device comprises a first transmission part and a second transmission part which are combined into a V shape, and the objective table is arranged on the end side of the first transmission part and the end side of the second transmission part and located in an exposure area. The objective table is used for bearing a to-be-exposed sample with a photosensitive material, the first reflecting mirror and the second reflecting mirror are arranged on the side of the objective table, the light source passes through the beam splitter and is provided with two beams of coherent light, namely first coherent light and second coherent light, the first coherent light is reflected by the first reflecting mirror and then falls on the objective table, the second coherent light is reflected by the second reflecting mirror and then falls on the objective table, and the two beams of coherent light are used for exposure. And batch exposure can be carried out by adopting the V-shaped conveying device.

Description

Technical Field

[0001] This application relates to the field of photolithography technology, and in particular to a V-shaped volume grating batch exposure apparatus and exposure control method. Background Technology

[0002] A volume Bragg grating (VBG) is a three-dimensional diffractive optical element that achieves beam manipulation through periodic modulation of the refractive index within a photosensitive material. In recent years, it has demonstrated unique advantages in laser technology, optical communication, and quantum optics. VBGs feature ultra-narrow bandwidth, high diffraction efficiency, low power loss, low temperature drift coefficient, small size, stable performance, and long lifespan, making them widely applicable in optical communication, lasers, instrumentation, and biomedicine. In the laser field, VBGs are a novel laser component that can be used as laser mirrors in the manufacture of fiber lasers and semiconductor lasers. They can withstand high laser power densities, achieving wavelength locking, linewidth narrowing, longitudinal / transverse mode selection, and outputting lasers with stable wavelengths.

[0003] Currently, mass production of grating structures is achieved through high-precision photolithography, holographic interferometry, laser direct writing, and nanoimprinting. Among these, holographic interferometry has become one of the important processes for the mass production of volume Bragg gratings (VBGs) due to its high precision, high uniformity, and large-area processing capabilities. However, it also has drawbacks such as insufficient positioning accuracy, poor repeatability and consistency, increased environmental interference, and risks of contamination and damage. Summary of the Invention

[0004] To overcome the above-mentioned shortcomings, this application proposes a V-shaped volume grating batch exposure device, which can realize the standardization and large-scale production of volume gratings and greatly improve production efficiency.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] A V-shaped volume grating batch exposure apparatus, comprising:

[0007] Light source, beam splitter, first reflector, second reflector, transmission device, and stage.

[0008] The transmission device includes a first transmission component and a second transmission component, which are combined in a V-shape.

[0009] The stage is disposed at the end of the first and second transmission components and is located in the exposure area. The stage is used to hold the sample containing photosensitive material to be exposed.

[0010] The first and second reflectors are disposed on the side of the stage.

[0011] The light source is split into two coherent beams by the beam splitter: a first coherent beam and a second coherent beam.

[0012] The first coherent light, after being reflected by the first mirror, falls onto the stage.

[0013] The second coherent light, after being reflected by the second mirror, falls onto the stage. The sample is then exposed by combining the reflected first and second coherent light. This method utilizes the combined reflection of the first and second coherent light to form interference fringes within the photosensitive material, inducing periodic refractive index modulation within the photosensitive material.

[0014] Preferably, the sample is photothermal refractive glass.

[0015] Preferably, the grating period Λ is precisely set by adjusting the angle θ between the first coherent light and the second coherent light.

[0016] Preferably, the sample is placed on the stage and located at the confluence of the first coherent light and the second coherent light after reflection.

[0017] Preferably, the first transmission component is provided with a first magnetic levitation conveyor belt, and the second transmission component is provided with a second magnetic levitation conveyor belt.

[0018] Preferably, the first transmission component and the second transmission component are located inside the first coherent light and the second coherent light.

[0019] Preferably, the first magnetic levitation conveyor belt and the second magnetic levitation conveyor belt are both carbon fiber base belts.

[0020] Preferably, the V-shaped volumetric grating batch exposure apparatus includes a first fixing component and a second fixing component, each of which is equipped with an adjustment component.

[0021] The first fixing component fixes the first reflector, the second fixing component fixes the second reflector, and the adjustment component adjusts the posture of the first reflector and the second reflector.

[0022] Preferably, the first reflector and the second reflector are symmetrically arranged along the centerline of the first transmission component and the second transmission component.

[0023] This application provides an exposure control method for the above-described V-shaped volume grating batch exposure apparatus, the method comprising the following steps:

[0024] The sample to be exposed is transmitted to the stage along the direction of the first coherent light using the first transmission component.

[0025] The sample is exposed after the first coherent light and the second coherent light reflected from the sample on the stage are combined, forming interference fringes inside the sample.

[0026] After exposure, the sample is transported to a predetermined position by a second transmission component along the direction opposite to the second coherent light. This method employs a V-shaped sample transport, avoiding interference with light propagation, shortening loading time, and improving production efficiency.

[0027] Beneficial effects

[0028] Compared with existing technologies, the exposure apparatus proposed in this application employs a V-shaped conveyor device located inside the light beam. This avoids interference with the optical path caused by sample movement during exposure, facilitating standardized and large-scale production and significantly improving production efficiency. Simultaneously, real-time temperature and humidity monitoring reduces stripe drift and achieves a stable light field. Attached Figure Description

[0029] The accompanying drawings are provided to illustrate the technical solutions of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the technical solutions of this disclosure and do not constitute a limitation on the technical solutions of this disclosure. The shapes and sizes of the components in the drawings do not reflect actual proportions and are only intended to illustrate the content of this application.

[0030] Figure 1 This is a schematic diagram of the optical path of the exposure apparatus in an embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the V-shaped transmission device of the exposure apparatus in the embodiments of this application;

[0032] Figure 3 This is a flowchart illustrating the control method according to an embodiment of this application. Detailed Implementation

[0033] The above-described solution will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application. The implementation conditions used in the embodiments may be further adjusted according to the conditions of specific manufacturers, and the implementation conditions not specified are generally those in routine experiments.

[0034] In this application, the terms "upper," "lower," "inner," "middle," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0035] A volume grating is a three-dimensional periodic refractive index modulation structure formed within a transparent medium (such as glass, crystal, or photoresist), with its period typically ranging from submicron to nanometer scale. Unlike surface gratings, the optical properties of a volume grating are determined by the holographic structure within the material, offering advantages such as high diffraction efficiency, narrow bandwidth selectivity, and a high damage threshold. The fabrication of volume gratings relies on photolithography, the core of which involves forming a periodic structure within the medium through the interaction of light and material. As mentioned in the background section, current fabrication methods enable stable and reliable mass production. However, manual operation makes it difficult to guarantee absolute consistency in placement each time, potentially leading to non-uniform grating periods, reduced diffraction efficiency, or increased stray light.

[0036] Based on this, this application proposes a V-shaped volumetric grating batch exposure device, which can achieve standardized and large-scale production and greatly improve production efficiency.

[0037] Next, combine Figures 1-3 This application describes the V-shaped oriented volume grating batch exposure apparatus (hereinafter referred to as the exposure apparatus) and its control method.

[0038] The exposure apparatus includes:

[0039] The system includes a light source 100, a beam splitter 200, a first reflector 310, a second reflector 320, a transmission device 500, and a stage 400.

[0040] The transmission device 500 includes a first transmission component 510 and a second transmission component 520, which are combined in a V-shape.

[0041] The stage 400 is disposed at the end (intersecting side) of the first transmission component 510 and the second transmission component 520 and is located in the exposure area. The stage 400 is used to hold the sample containing photosensitive material to be exposed.

[0042] The first reflecting mirror 310 and the second reflecting mirror 320 are disposed on the side of the stage 400.

[0043] The light source 100 is split into two coherent beams by the beam splitter 200: a first coherent beam 110 and a second coherent beam 120.

[0044] The first coherent light 110, after being reflected by the first reflecting mirror 310, falls onto the stage 400.

[0045] The second coherent light 120, after being reflected by the second reflector 320, falls onto the stage 400. The reflected first coherent light 110 and second coherent light 120 are combined to expose the sample. This exposure device is based on holographic interference exposure technology. A beam splitter divides a single laser into two coherent beams, forming spatial interference fringes within the photosensitive material (such as photothermal refractive glass PTR). This induces periodic refractive index modulation (e.g., when the combined beam is incident on the PTR glass, interference occurs inside the PTR glass, forming interference fringes). The combination of the first coherent light 110 and the second coherent light 120 forms a V-shape. By adjusting the angle θ between the two beams (the angle θ between the first coherent light 110 and the second coherent light 120), the grating period Λ can be precisely calculated and set, reaching the sub-nanometer level. In this embodiment, the stage is located at the point where the two beams converge (the interference region is ). A V-shaped conveyor device is used for batch exposure, maximizing the number of samples that can be loaded and reducing manual operation and interference. The V-shaped conveyor, positioned inside the two beams, effectively avoids the device's influence on light propagation, shortens the feeding time, and improves production efficiency.

[0046] The device is positioned between two coherent light beams to prevent the beams from affecting the pre-exposed material (photosensitive material) during exposure. The first transmission component 510 and the second transmission component 520 are independently configured, with their independent V-shaped magnetic levitation conveyor belts intersecting at an angle, forming the core channel for sample transport and alignment. In one embodiment, a six-degree-of-freedom precision adjustment frame is located below the stage at the intersection, allowing seamless connection with the conveyor belts of the first and second transmission components 510 and 520, supporting precise adjustment of X, Y, and Z-axis translation, pitch angle, and rotation angle. Material is loaded along the light propagation path, maximizing the transmission distance and increasing the quantity loaded per batch. The raw material is precisely positioned from the loading port to the exposure station via the V-shaped conveyor belt, and the precision six-degree-of-freedom adjustment frame quickly levels it, achieving batch exposure of the volume grating. This embodiment, through the deep integration of the V-shaped magnetic levitation conveyor belt and the six-degree-of-freedom adjustment frame, achieves intelligent alignment capabilities down to the micrometer level, combining high-speed transport with precise adjustment characteristics. The angle θ1 between the first transmission component 510 and the second transmission component 520 is the same as or approximately the same as the angle θ between the first coherent light 110 and the second coherent light 120. Preferably, the angle θ1 is the same as or approximately the same as the angle θ between the first coherent light 110 and the second coherent light 120.

[0047] In one embodiment, the conveyor belts of the first transmission component 510 and the second transmission component 520 are flat belts, employing magnetic levitation drive and servo motor closed-loop control. This ensures high repeatability and positioning accuracy, and contactless transmission, reducing interference to the vibration isolation platform. Preferably, the conveyor belts are made of carbon fiber base belts to strictly guarantee cleanliness.

[0048] In one embodiment, a temperature and humidity sensor is provided on the stage side to detect the temperature and humidity information of the exposure area in real time, thereby reducing stripe drift and achieving a stable light field. Preferably, the temperature and humidity sensor feeds back the temperature and humidity information to the control module, which then adjusts the light source to reduce stripe drift and achieve a stable light field.

[0049] The exposure apparatus proposed in this application utilizes a V-shaped mechanical conveyor to place photosensitive glass materials, enabling multi-sheet exposure production in one operation. The V-shaped structure effectively avoids interference with the optical path, increases the amount of material fed, improves production efficiency, and achieves efficient and high-quality mass production of gratings.

[0050] Based on the same concept, this application provides an exposure control method, such as... Figure 3 As shown, the method includes the following steps:

[0051] The sample to be exposed is transferred to the stage along the direction of the first coherent light (incident direction) using a first transmission component. This step includes using a transmission device, such as a robotic arm, to place the sample to be exposed from the loading port onto the first transmission component, and then transferring it to the stage based on the first transmission component (magnetic levitation conveyor belt). A robotic arm is installed on the side of the stage to place the sample to be exposed onto the stage. The robotic arm is existing technology and its structure will not be described in detail here; it is sufficient to achieve the function of placing the sample onto the stage. This method maximizes the number of samples that can be loaded, reduces manual operation and interference, and is beneficial for continuous batch exposure operations.

[0052] The sample is exposed after the first coherent light and the second coherent light reflected from it are combined, forming interference fringes inside the sample; this step includes exposing the sample after the first coherent light and the second coherent light are combined, forming spatial interference fringes inside the sample.

[0053] After exposure, the sample is transported to a predetermined position via a second transmission component along the direction opposite to the second coherent light (incident direction). A robotic arm is mounted on the stage side, which places the sample to be exposed onto the second transmission component. The robotic arm is existing technology and its structure will not be described in detail here; its function is simply to place the sample onto the second transmission component. In this step, the sample is transported to the unloading port along the direction opposite to the second coherent light via the second transmission component, and then proceeds to the next process (such as packaging).

[0054] This embodiment includes splitting the light from a light source (such as a laser) into two beams (a first coherent beam and a second coherent beam) using a beam splitter. Preferably, the light source is electrically connected to and controlled by a control module. Preferably, the control module controls the light source in response to temperature and humidity information fed back from a temperature and humidity sensor, reducing fringe drift and achieving a stable light field. A V-shaped transmission device is located inside the two beams.

[0055] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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, they should be considered to be within the scope of this specification.

[0056] The above embodiments are only for illustrating the technical concept and features of this application, and are intended to enable those skilled in the art to understand the content of this application and implement it accordingly. They should not be used to limit the scope of protection of this application. All equivalent changes or modifications made in accordance with the spirit and essence of this application should be included within the scope of protection of this application.

Claims

1. A batch exposure apparatus for V-shaped oriented volume gratings, characterized in that, include: Light source, beam splitter, first reflector, second reflector, transmission device, and stage. The transmission device includes a first transmission component and a second transmission component, which are combined in a V-shape. The stage is disposed at the end of the first and second transmission components and is located in the exposure area. The stage is used to hold the sample containing photosensitive material to be exposed. The first and second reflectors are disposed on the side of the stage. The light source is split into two coherent beams by the beam splitter: a first coherent beam and a second coherent beam. The first coherent light, after being reflected by the first mirror, falls onto the stage. The second coherent light is reflected by the second mirror and falls onto the stage. The sample is exposed by combining the reflected first coherent light with the second coherent light.

2. The V-shaped oriented volume grating batch exposure apparatus as described in claim 1, characterized in that, The sample is photothermal refractive glass.

3. The V-shaped oriented volume grating batch exposure apparatus as described in claim 1, characterized in that, The grating period Λ is precisely set by adjusting the angle θ between the first coherent light and the second coherent light.

4. The V-shaped oriented volume grating batch exposure apparatus as described in claim 1, characterized in that, The sample is placed on the stage and is located at the confluence of the first coherent light and the second coherent light after reflection.

5. The V-shaped oriented volume grating batch exposure apparatus as described in claim 4, characterized in that, The first transmission component is equipped with a first magnetic levitation conveyor belt, and the second transmission component is equipped with a second magnetic levitation conveyor belt.

6. The V-shaped oriented volume grating batch exposure apparatus as described in claim 5, characterized in that, The first transmission component and the second transmission component are located inside the first coherent light and the second coherent light, respectively.

7. The V-shaped oriented volume grating batch exposure apparatus as described in claim 5, characterized in that, The first magnetic levitation conveyor belt and the second magnetic levitation conveyor belt are both carbon fiber base belts.

8. The V-shaped oriented volume grating batch exposure apparatus as described in claim 1, characterized in that, It includes a first fixing component and a second fixing component, each of which is provided with an adjustment component. The first fixing component fixes the first reflector, the second fixing component fixes the second reflector, and the adjustment component adjusts the posture of the first reflector and the second reflector.

9. The V-shaped oriented volume grating batch exposure apparatus as described in claim 8, characterized in that, The first reflector and the second reflector are symmetrically arranged along the centerline of the first transmission component and the second transmission component.

10. An exposure control method, characterized in that, The method, comprising the V-shaped oriented volume grating batch exposure apparatus as described in any one of claims 1-9, includes the following steps: The sample to be exposed is transmitted to the stage along the direction of the first coherent light using the first transmission component. The first coherent light and the second coherent light reflected from the sample on the stage are combined and exposed to form interference fringes inside the sample. The exposed sample is transported to a predetermined position by the second transmission component along the direction opposite to the second coherent light.

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