Cascade attenuation structure and installation method based on light pipe sampling, detection array

Abstract

The present invention relates to a cascade attenuation structure and installation method and a detection array based on light guide sampling, which solves the problem that the attenuation multiple of a strong light attenuator is difficult to adjust over a large range, and the strong light protection and attenuation sampling are highly coupled, resulting in limited improvement in protection capability. The present invention includes a protective plate, a light guide and an attenuator; the front surface of the protective plate is provided with a laser protection layer, and a through hole is provided axially; the light guide is located in the through hole, and one end thereof is flush with the front surface of the laser protection layer, and the other end is connected to the front end of the attenuator; the rear end of the attenuator is connected to an output plate, and the attenuator and the output plate cooperate with each other to form an attenuator cavity; the front end of the attenuator is provided with an input hole corresponding to the other end of the light guide; the output plate is provided with an output hole; a number of light shielding plates are installed in the attenuator cavity, and the light shielding plates divide the attenuator cavity into a plurality of small attenuator cavities; at least one optical channel is provided on the light shielding plates. The present invention is used for high energy density laser measurement.

Description

Technical Field

[0001] The invention relates to a cascade attenuation structure, and in particular to a cascade attenuation structure based on light guide tube sampling, an installation method and a detection array. Background Art

[0002] In the measurement of high-energy laser parameters, the array method based on photoelectric array detectors is a commonly used method. In order to achieve direct measurement of strong light, quantitative attenuation is required, and strong light protection is also required before detection by photoelectric detector array. Currently, the commonly used optical attenuation methods mainly include filter attenuation method, scattering attenuation method, and integrating sphere attenuation method. In the filter attenuation method, since the filter is sensitive to the incident angle and its attenuation coefficient is difficult to accurately calibrate when the attenuation is large, the filter transmittance is related to the laser wavelength and the incident angle, which limits its application scope in high-energy laser measurement. The scattering attenuation method uses an optical scattering device to spatially scatter the incident laser, and then uses a detector to measure the scattered light; the integrating sphere attenuation method uses an integrating sphere array to attenuate the high-energy laser to achieve high-energy laser measurement.

[0003] A Chinese patent with publication number CN102384783A discloses a high-energy laser semi-integrating sphere array attenuator, which uses a large-angle sampling cone hole combined with a semi-integrating sphere to achieve laser attenuation. The laser is absorbed by the semi-integrating sphere cavity and diffusely reflected, and then emitted from the laser exit hole, achieving a significant attenuation of the laser power density. A Chinese patent with publication number CN104019891A discloses an attenuation sampling device for high-energy lasers with large-angle incidence, including a sampling straight hole, an exit hole, and a cylindrical cavity. The cylindrical cavity is filled with granular optical body scattering materials, which can achieve large-angle attenuation sampling when the laser is obliquely incident. A Chinese patent with publication number CN109579983A discloses a beam sampler for measuring the intensity distribution parameters of high-energy lasers. Through the combination of a straight hole diffuse reflection cavity and a diffuse reflection film, a large-multiple homogenized attenuation of the laser is achieved. The inverted cone hole sampling structure is combined with a method of polishing the light-facing surface of the attenuator front panel with a mirror-coated high-reflection film, and the attenuator large-angle sampling and strong light protection are achieved at the same time. The above-mentioned attenuation samplers or devices are applicable to the measurement of strong light at the kilowatt level per square centimeter, and have been successfully applied. However, when the laser intensity increases significantly or the light emission time reaches the minute level, the above-mentioned attenuation samplers are no longer applicable. The main reason is that the above-mentioned attenuation structures all use cone hole sampling. In order to meet the requirements of large field of view detection, the sampling hole and the attenuation structure must be processed inside the protection panel, resulting in a high degree of coupling between protection and sampling attenuation. Since the sampling attenuation structure is difficult to work at high temperatures, the working temperature of the protection panel is limited, which limits the performance indicators and application scope of the protection panel and the attenuation sampling device, making it difficult to use in higher energy density laser measurements.

[0004] In addition, in practical applications, after most strong light attenuators are processed, their attenuation multiples are difficult to adjust over a wide range. Due to the limitations of the processing technology, the actual attenuation multiples of the scattering attenuator often deviate greatly from the design value, increasing the uncertainty and risk of equipment development. In the requirements of high spatial resolution detection, high requirements are placed on the miniaturization of the attenuator, so it is very necessary to design a miniaturized attenuator with a wide range of adjustable attenuation multiples. Summary of the invention

[0005] The present invention provides a cascade attenuation structure and an installation method and a detection array based on light guide sampling, which are used to solve the problem that the attenuation multiple of the existing strong light attenuator is difficult to adjust over a large range, and the strong light protection and attenuation sampling are highly coupled, resulting in limited improvement in protection capability. The structure can be used for high energy density laser measurement.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A cascade attenuation structure based on light pipe sampling, which is special in that it includes a protective plate, a light pipe and an attenuator;

[0008] The front surface of the protection plate is provided with a laser protection layer, the protection plate is provided with a through hole in the axial direction, and the laser protection layer is provided with a through hole corresponding to the through hole in the axial direction;

[0009] The light guide is located in the through hole, and one end of the light guide is flush with the front surface of the laser protection layer, and the other end is connected to the front end of the attenuator; the diameter of the through hole is larger than the diameter of the light guide;

[0010] The rear end of the attenuator is connected to an output plate, and the attenuator and the output plate cooperate with each other to form an attenuator cavity;

[0011] The front end of the attenuator is provided with an input hole corresponding to the other end of the light guide tube, so that the light guide tube is connected with the attenuator cavity;

[0012] The output plate is provided with an output hole;

[0013] A plurality of radially arranged light-blocking sheets are installed in the attenuator cavity, and the light-blocking sheets divide the attenuator cavity into a plurality of small attenuator cavities;

[0014] At least one optical channel is arranged on the light blocking plate, so that the optical paths between the plurality of small attenuator cavities are connected.

[0015] Furthermore, a light blocking sheet is installed in the attenuator cavity to form a two-stage attenuation structure;

[0016] The light blocking sheet divides the attenuator cavity into a first attenuator cavity and a second attenuator cavity;

[0017] The first attenuator cavity is in communication with the light guide tube, and the second attenuator cavity is in communication with the output hole;

[0018] A scattering sheet is fixedly installed in each of the first attenuator cavity and the second attenuator cavity.

[0019] Furthermore, at least two light-blocking sheets are arranged in the attenuator cavity to form a multi-stage attenuation structure;

[0020] The light blocking sheet divides the attenuator cavity into a first attenuator cavity, a second attenuator cavity, a third attenuator cavity and an Nth attenuator cavity in sequence, where N≥3;

[0021] Scattering sheets are fixedly installed in the first attenuator cavity, the second attenuator cavity, the third attenuator cavity and the Nth attenuator cavity.

[0022] Furthermore, the light channel is one and is located at the center of the light shielding sheet;

[0023] Or there are multiple light channels, and the multiple light channels are evenly distributed around the edges of the light blocking sheet and are axially symmetrical.

[0024] Furthermore, a light guide fixing plate is provided between the protection plate and the attenuator for fixing the light guide, and a mounting hole matching the diameter of the light guide is processed on the light guide fixing plate.

[0025] Furthermore, the light guide tube is cylindrical; or the light guide tube is cylindrical and the rear end of the cylinder is a T-shaped structure or a countersunk type.

[0026] Furthermore, the cylindrical surface of the light guide tube is an optical-grade smooth surface, the light-facing surface is an optical-grade smooth surface, and the output end surface is a diffuse reflection surface.

[0027] Furthermore, the light guide tube is made of high-purity materials such as high-purity quartz and aluminum oxide.

[0028] A method for installing a cascade attenuation structure based on light pipe sampling is special in that the steps are as follows:

[0029] Step 1, fix the light guide tube on the fixing plate, and then connect the fixing plate to the front end of the attenuator;

[0030] Step 2, according to the attenuator cascade design result, first install a scattering sheet and then install a light blocking sheet in the attenuator cavity of the attenuator until the cascade attenuation structure in the cavity meets the design requirements;

[0031] Step 3: After the cascade scattering attenuation structure is installed, the output board is installed at the rear end of the attenuator to complete the installation of the attenuator;

[0032] Step 4, making a protective layer on the light-facing side of the protective plate;

[0033] Step 5: Tightly connect the manufactured protective plate and the fixing plate with bolts to complete the installation of the entire attenuation structure.

[0034] A cascade attenuation structure detection array based on light pipe sampling is special in that it includes multiple cascade attenuation structures based on light pipe sampling as described above, the multiple cascade attenuation structures based on light pipe sampling are parallel to each other and connected through positioning pin holes set on the panel to form a detection array.

[0035] Compared with the existing solutions, the beneficial effects of the present invention are as follows:

[0036] 1. The attenuation structure of the present invention solves the problem that the strong light protection and laser sampling attenuation in the commonly used pinhole attenuation sampling structure limit each other, making it difficult to significantly improve the protection capability, and realizes the decoupling design between laser protection and sampling attenuation, which can significantly improve the laser protection capability. Specifically, compared with the commonly used pinhole sampling attenuation structure, the cylindrical light guide in the attenuation structure realizes large-angle laser sampling and light guiding based on the principle of total internal reflection, which is independent of the laser protection panel and can realize the decoupling of sampling and protection; since the length of the light guide is not limited, the attenuator and the laser protection panel can be completely isolated to realize the decoupling of protection and attenuation; secondly, the light guide adopts high-temperature resistant optical materials, and its sampling characteristics are only related to the refractive index of the material, and can work at high temperatures. Combined with the heat insulation design of the light guide and the panel, the laser protection panel can realize high-temperature operation, which greatly improves the thermal bearing capacity of the laser protection panel and significantly enhances the strong light protection capability.

[0037] 2. In the attenuation structure of the present invention, the light guide tube is made of high-purity materials such as high-purity quartz and aluminum oxide, and has the advantage of a large laser detection field of view, and can achieve a detection field of view better than ±50°.

[0038] 3. In the attenuation structure of the present invention, the attenuation adopts cascade scattering attenuation. By replacing scattering sheets of different sizes and changing the position of the cascade light-blocking sheets in the cavity and the number of light-blocking sheets, the attenuation can be easily adjusted over a wide range to meet the design requirements of the attenuator miniaturization. According to the relationship curve between the cascade attenuation multiple and the position of the light-blocking sheet, and the attenuation multiple change curve when the light-blocking sheet is located at different positions, it can be seen that the adjustment range can reach 1 order of magnitude.

[0039] 4. In the attenuation structure of the present invention, the optical processing method can realize the processing of the light guide with a millimeter-level diameter, and the diameter of the attenuation cavity can also be designed and manufactured at the millimeter level. Therefore, the radial dimension of the attenuation structure based on the light guide and the attenuation cavity can reach the millimeter level, and a millimeter-level array arrangement can be realized, meeting the requirements of high spatial resolution measurement of the light spot. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1Schematic diagram of the cascade scattering attenuation structure based on light pipe sampling in the first embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the structure of a countersunk light guide tube in Embodiment 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of the structure of a light shielding sheet with four-round holes in the first embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of the structure of a central circular hole type light blocking sheet in Embodiment 1 of the present invention;

[0044] Figure 5 This is a schematic diagram of the structure of a rib-type light-blocking sheet in Embodiment 1 of the present invention;

[0045] Figure 6 This is a schematic diagram of a two-stage cascade attenuation combination in Embodiment 1 of the present invention;

[0046] Figure 7 is a curve showing the relationship between the two-stage cascade attenuation multiple and the position of the light-blocking sheet in the first embodiment of the present invention;

[0047] Figure 8 is the angle characteristic curve of the light guide tube in the first embodiment of the present invention;

[0048] Fig. 9 Schematic diagram of the attenuation sampling array in the first embodiment of the present invention;

[0049] Fig.10 Schematic diagram of the three-stage cascade attenuation combination in the second embodiment of the present invention Figure 1 ;

[0050] Fig.11 Schematic diagram of the three-stage cascade attenuation combination in the second embodiment of the present invention Figure 2 .

[0051] The specific reference numerals are as follows:

[0052] 1—laser protection layer; 2—through hole; 3—light guide fixing plate; 4—scattering plate; 5—light blocking plate; 7—output plate; 8—protection plate; 9—light guide; 10—input hole; 11—attenuator; 12—optical channel; 13—attenuator cavity; 14—output hole. DETAILED DESCRIPTION

[0053] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0054] Embodiment 1

[0055] like Figure 1As shown, the present invention provides a cascade attenuation structure based on light pipe sampling, including a protective plate 8, a laser protective layer 1 for high reflection of incident laser is provided on the front surface of the protective plate 8, and a through hole 2 is processed axially on the protective plate 8. The laser protective layer 1 can be realized by plating a high-reflection metal film or a medium high-reflection film on the surface of the protective plate 8 or bonding a whole piece of reflective lens. When the laser protective layer 1 is prepared by a bonded reflector to realize laser protection, a through hole corresponding to the through hole 2 needs to be processed on the reflector to avoid affecting the sampling of other structures.

[0056] A light guide tube 9 is disposed in the through hole 2 , so that the diameter of the through hole 2 is larger than that of the light guide tube 9 and the through hole 2 is flush with the front end of the light guide tube 9 , thereby isolating the light guide tube 9 from the protective plate 8 .

[0057] The light guide tube 9 is a cylindrical tube processed by an optical processing method. The cylindrical surface of the light guide tube 9 is an optically smooth surface to meet the boundary conditions of light conduction. The light-facing surface is an optically smooth surface, and the output end surface is a diffuse reflection surface.

[0058] The light guide 9 is a cylinder made of high-purity optical materials such as quartz or aluminum oxide by optical processing. The cylindrical surface of the light guide 9 is an optically smooth surface, the light-facing surface is an optically smooth surface, and the output end surface is a diffuse reflection surface to meet the boundary conditions of light transmission. Light is transmitted in the light guide 9 based on the principle of total internal reflection, which is similar to optical fiber transmission. The air can be regarded as the cladding of the optical fiber, and its field of view half angle θ is given by Calculation shows that the refractive index of air N0=1, the refractive index of the light guide 9 N1≈1.7 (refractive index of aluminum oxide) or N1≈1.5 (refractive index of quartz), and it can be seen that its field of view half angle θ is greater than 90°. Figure 8 As shown in the angle characteristic curve, when the relative amplitude is reduced to 0.6, the corresponding field of view angle also reaches ±50°.

[0059] There are many structural variations, such as solid round tube, T-shaped structure or Figure 2 The countersunk type shown effectively changes the installation method of the light guide 9 by changing the appearance of the light guide 9, thereby increasing the freedom of overall structural design.

[0060] The end of the light guide 9 is connected to an attenuator 11, and an input hole 10 corresponding to the light guide 9 is processed at the front end of the attenuator 11. The end of the attenuator 11 is connected to the output plate 7. The attenuator 11 cooperates with the output plate 7 to form a cylindrical attenuator cavity 13. The output plate 7 is processed with an output hole 14, and the attenuator 11 outputs the attenuated light beam from the output hole 14.

[0061] A light guide fixing plate 3 is arranged between the protective plate 8 and the attenuator 11 for fixing the light guide 9. A mounting hole matching the diameter of the light guide 9 is processed on the light guide fixing plate 3. The surface of the mounting hole is treated to be a rough surface. The light guide fixing plate 3 and the light guide 9 are fixed by high-temperature resistant glue or high-temperature welding.

[0062] In order to improve the applicability of the system, the protection panel 2 and the light guide fixing plate 3 can be designed as independent installation structures to achieve rapid replacement at the test site.

[0063] like Figure 6 As shown, a circular light shielding sheet 5 is installed in the attenuator cavity 13 to form a two-stage attenuation structure. The light shielding sheet 5 evenly divides the attenuator cavity 13 into a first attenuator cavity and a second attenuator cavity. The first attenuator cavity is connected to the light pipe 9, and the second attenuator cavity is connected to the output hole 14. Figure 3 and Figure 4 The light shielding sheet 5 shown in the figure has a light channel 12 processed at the center of the light shielding sheet 5 or four evenly distributed and symmetrical light channels 12 processed around the light shielding sheet 5, so that the first attenuator cavity and the second attenuator cavity are connected through the light channel 12. The shape of the light channel 12 can be various, including a circular hole, a rib shape, etc. Figure 5 As shown, the rib-shaped light channel forms a light channel 12 through the area surrounded by the light blocking plate 5 and the inner wall of the attenuation cavity.

[0064] The first attenuator cavity and the second attenuator cavity are both provided with scattering sheets 4 , which are fixedly installed by optical adhesive bonding or by pressing the output plate 7 .

[0065] In the attenuator cavity 13, the position of the light blocking sheet 5 and the size of the light channel 12 are adjusted by adjusting and replacing the scattering sheets 4 of different thicknesses, and finally the attenuation multiple is adjusted. The relationship between the attenuation multiple and the adjustment position is as follows: Figure 7 shown.

[0066] After the incident laser enters the light guide 9, it passes through the input hole 10 and enters the first attenuator cavity. After being scattered by the scattering plate 4 in the first attenuator cavity, the laser passes through the optical channel 12 and enters the second attenuator cavity. After being scattered by the scattering plate 4 in the second attenuator cavity, the laser is finally output through the output hole 14.

[0067] In order to achieve large spot measurement, the above-mentioned cascade attenuation structure based on light pipe sampling is arranged in an array to form a large-area detection array such as Fig. 9 As shown, since the circumference size of the attenuation structure can reach the millimeter level, the spot measurement with millimeter-level spatial resolution can be achieved. In order to ensure the consistency and reliability of the attenuator, positioning pin holes are designed on the laser protection panel to ensure stable arrangement after installation.

[0068] The installation process of the cascade attenuation structure based on light pipe sampling provided by the present invention can be carried out in the following steps:

[0069] Step 1: fix the light guide 9 on the fixing plate 3, and then accurately connect the fixing plate 3 and the front end of the attenuator 11 through the positioning hole.

[0070] Step 2: According to the cascade design result of the attenuator 11, first install the scattering plate 4 and then install the light blocking plate 5 in the attenuation cavity of the attenuator 11 until the cascade scattering attenuation structure in the cavity meets the design requirements.

[0071] Step 3, after the cascade scattering attenuation structure is installed, the output plate 7 is installed at the rear end of the attenuator 11 to complete the installation of the attenuator 11. When the attenuation multiple of the attenuator 11 needs to be changed, it is only necessary to take out the internal scattering sheet 4 and the light blocking sheet 5 and reassemble and install them.

[0072] Step 4, making a protective layer 1 on the light-facing surface of the protective plate 8.

[0073] Step 5: tightly connect the manufactured protective plate 8 and the fixing plate 3 by bolts to complete the installation of the entire attenuation structure.

[0074] Embodiment 2

[0075] When the cascade attenuation structure of the attenuator 11 is a multi-stage attenuation, a larger multiple of attenuation adjustment can be achieved.

[0076] like Fig.10 and Fig.11 As shown, at least two light shielding sheets 5 are arranged in the attenuator cavity 13, and a first attenuator cavity, a second attenuator cavity, a third attenuator cavity and an Nth attenuator cavity are formed in sequence, where N≥3;

[0077] Each light blocking sheet 5 is processed with a light channel 12 at the center or four light channels 12 are symmetrically processed and evenly distributed.

[0078] Scattering plates 4 are installed in the first attenuator cavity, the second attenuator cavity, the third attenuator cavity and the Nth attenuator cavity.

[0079] In case of multi-level attenuation, different types of light blocking sheets 5 and scattering sheets 4 with different thickness specifications can be used to achieve attenuation adjustment, thereby achieving a wider range of adjustment.

Claims

1. A cascade attenuation structure based on light pipe sampling, characterized in that: It comprises a protective plate (8), a light guide tube (9) and an attenuator (11); The front surface of the protection plate (8) is provided with a laser protection layer (1), the protection plate (8) is axially provided with a through hole (2), and the laser protection layer (1) is axially provided with a through hole corresponding to the through hole (2); The light guide tube (9) is located in the through hole (2), and one end of the light guide tube (9) is flush with the front surface of the laser protection layer (1), and the other end is connected to the front end of the attenuator (11); the diameter of the through hole (2) is larger than the diameter of the light guide tube (9); The rear end of the attenuator (11) is connected to an output plate (7), and the attenuator (11) and the output plate (7) cooperate with each other to form an attenuator cavity (13); The front end of the attenuator (11) is provided with an input hole (10) corresponding to the other end of the light guide tube (9), so that the light guide tube (9) is connected to the attenuator cavity (13); The output plate (7) is provided with an output hole (14); A plurality of radially arranged light shielding sheets (5) are installed in the attenuator cavity (13), and the light shielding sheets (5) divide the attenuator cavity (13) into a plurality of small attenuator cavities; At least one optical channel (12) is provided on the light blocking plate (5), so that the optical paths between the multiple small attenuator cavities are connected.

2. The cascade attenuation structure based on light pipe sampling according to claim 1, characterized in that: A light blocking sheet (5) is installed in the attenuator cavity (13) to form a two-stage attenuation structure; The light blocking plate (5) divides the attenuator cavity (13) into a first attenuator cavity and a second attenuator cavity; The first attenuator cavity is in communication with the light guide tube (9), and the second attenuator cavity is in communication with the output hole (14); A scattering sheet (4) is fixedly installed in both the first attenuator cavity and the second attenuator cavity.

3. The cascade attenuation structure based on light pipe sampling according to claim 1, characterized in that: At least two light blocking sheets (5) are arranged in the attenuator cavity (13) to form a multi-stage attenuation structure; The light blocking sheet (5) sequentially divides the attenuator cavity (13) into a first attenuator cavity, a second attenuator cavity, a third attenuator cavity and an Nth attenuator cavity, where N≥3; A scattering sheet (4) is fixedly installed in each of the first attenuator cavity, the second attenuator cavity, the third attenuator cavity and the Nth attenuator cavity.

4. A cascade attenuation structure based on light pipe sampling according to claim 2 or 3, characterized in that: The light channel (12) is one and is located at the center of the light blocking sheet (5); Alternatively, there are multiple light channels (12), and the multiple light channels (12) are evenly distributed and axially symmetrically located around the edges of the light blocking sheet (5).

5. The cascade attenuation structure based on light pipe sampling according to claim 4, characterized in that: A light guide tube fixing plate (3) is provided between the protection plate (8) and the attenuator (11) for fixing the light guide tube (9), and a mounting hole matching the diameter of the light guide tube (9) is machined on the light guide tube fixing plate (3).

6. The cascade attenuation structure based on light pipe sampling according to claim 5, characterized in that: The light guide tube (9) is cylindrical; or the light guide tube (9) is cylindrical and the rear end of the cylinder is a T-shaped structure or a countersunk type.

7. The cascade attenuation structure based on light pipe sampling according to claim 6, characterized in that: The cylindrical surface of the light guide tube (9) is an optical-grade smooth surface, the light-facing surface is an optical-grade smooth surface, and the output end surface is a diffuse reflection surface.

8. The cascade attenuation structure based on light pipe sampling according to claim 7, characterized in that: The light guide tube (9) is made of high-purity quartz or aluminum oxide.

9. A method for installing a cascade attenuation structure based on light pipe sampling, based on the cascade attenuation structure based on light pipe sampling according to any one of claims 1 to 8, characterized in that: The steps are as follows: Step 1, fix the light guide tube (9) on the fixing plate (3), and then connect the fixing plate (3) to the front end of the attenuator (11); Step 2, according to the cascade design result of the attenuator (11), first install the scattering plate (4) and then install the light blocking plate (5) in the attenuator cavity of the attenuator (11), until the cascade attenuation structure in the cavity meets the design requirements; Step 3, after the cascade scattering attenuation structure is installed, the output plate (7) is installed at the rear end of the attenuator (11), thereby completing the installation of the attenuator (11); Step 4, making a protective layer (1) on the light-facing surface of the protective plate (8); Step 5, tightly connecting the manufactured protective plate (8) and the fixing plate (3) by means of bolts, thereby completing the installation of the entire attenuation structure.

10. A cascade attenuation structure detection array based on light pipe sampling, characterized in that: It comprises a plurality of cascade attenuation structures based on light pipe sampling according to any one of claims 1 to 8, wherein the plurality of cascade attenuation structures based on light pipe sampling are parallel to each other and connected through positioning pin holes arranged on a panel to form a detection array.

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