A method for improving the laser damage resistance of a grating element by using a wet shallow etching

Abstract

The application discloses a method for improving the laser damage resistance of a grating element by using a wet shallow etching method, and comprises the following steps: spraying and cleaning the grating element; cleaning the grating element after the spraying and cleaning by using an alkali solution; wet shallow etching the grating element after the cleaning by using the alkali solution; rinsing the grating element after the wet shallow etching; and slowly pulling the grating element after the rinsing. The method can effectively remove the pollution or defects on the surface or subsurface of the grating element, greatly reduce the absorption of the laser energy by the grating element, improve the laser damage resistance of the grating element, prolong the service life of the grating element, and reduce the use cost of the grating element.

Description

Technical Field

[0001] This invention belongs to the field of optical element processing technology. More specifically, this invention relates to a method for improving the laser damage resistance of grating elements by using wet shallow etching. Background Technology

[0002] In high-power or high-energy laser devices, grating elements are used as spectral performance testing or beam splitting devices to achieve accurate diagnosis of laser beam quality or beam energy. During use, grating elements frequently suffer from surface damage induced by strong laser irradiation. This surface damage reduces the quality of the laser beam carried by the grating element, leading to failure of spectral performance testing or beam splitting functions. Surface damage significantly shortens the service life of grating elements. The usual solution is to replace the grating element promptly, which requires significant manpower and increases the cost of the grating components. Laser damage to the surface of grating elements is caused by contamination or defects on the surface or subsurface that readily absorb laser energy. Therefore, there is an urgent need for a method that can effectively remove contamination or defects from the surface or subsurface of grating elements to improve their resistance to laser damage, without compromising their original function and performance.

[0003] Currently, grating elements are manufactured according to the functional and performance requirements of their intended use. Therefore, to ensure their functionality and performance, grating elements cannot be reprocessed after initial fabrication and before integration. This means there are currently no technological solutions to address the issue of surface damage to grating elements, leaving users with no choice but to accept the cost of replacing damaged grating elements. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0005] To achieve these objectives and other advantages according to the present invention, a method for improving the laser damage resistance of grating elements using wet shallow etching is provided, comprising the following steps:

[0006] Step 1: Spray clean the grating element to remove particulate contaminants adhering to its surface;

[0007] Step 2: Clean the grating elements with alkaline solution after spray cleaning to remove organic contaminants from the surface of the grating elements;

[0008] Step 3: Perform wet shallow etching on the grating element after alkaline cleaning to remove subsurface defects of the grating element;

[0009] Step 4: Rinse the grating element after wet shallow etching to remove the residual etching solution and etching products after wet shallow etching.

[0010] Step 5: Slowly lift the rinsed grating element.

[0011] In step one, the cleaning solution used for spray cleaning of the grating element is one of the following: high-purity water with a resistivity ≥15MΩ·cm, 25wt% ethanol organic reagent solution, diluted 5wt% hydrochloric acid cleaning solution, or 5wt% sodium hydroxide alkaline cleaning solution.

[0012] Preferably, the specific method for spray cleaning the grating element in step one includes:

[0013] S11. Place the grating element in the middle of an array of nozzles with a jet velocity ≥2m / s. The grating element is placed vertically, and the jet direction is towards the surface of the grating element, angled downwards at a 30° angle to the surface of the grating element. The jet water temperature is 50℃, and the spraying time is 5 minutes.

[0014] S12. The grating element is fully immersed in a stainless steel tank containing high-purity water with a resistivity ≥15MΩ·cm. The water temperature is 50℃. The bottom of the tank has an ultrasonic plate. During the cleaning process, the frequency of the ultrasonic plate changes sequentially from 28kHz, 40kHz, 80kHz, 108kHz to 120kHz, with each frequency lasting for 3 minutes.

[0015] Preferably, in step two, the alkaline solution used for alkaline cleaning of the grating element after spray cleaning is sodium hydroxide or potassium hydroxide, or a mixed solution of sodium hydroxide and potassium hydroxide.

[0016] Preferably, in step two, the specific method for alkaline cleaning of the grating element after spray cleaning includes: immersing the grating element completely in a stainless steel tank containing a 5% sodium hydroxide solution at a temperature of 35°C, with an ultrasonic transducer plate at the bottom of the tank; during the cleaning process, the frequency of the ultrasonic transducer plate changes sequentially from 28kHz, 40kHz, 80kHz, 108kHz to 120kHz, with each frequency lasting for 5 minutes.

[0017] Preferably, in step three, the etching solution used for wet shallow etching of the grating element after alkaline cleaning includes one of hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid, sodium hydroxide, or potassium hydroxide.

[0018] Preferably, in step three, the specific method for wet shallow etching of the grating element after alkaline cleaning includes: immersing the grating element in a 0.5% hydrofluoric acid solution, the solution being contained in a polytetrafluoroethylene tank; an ultrasonic transducer is placed at the bottom of the tank; during the shallow etching process, the ultrasonic transducer frequency is 750kHz, the duration is 10 minutes, the temperature of the hydrofluoric acid solution is controlled at 30℃, and the shallow etching depth is 100nm.

[0019] Preferably, in step four, the rinsing solution used to rinse the grating element after wet shallow etching is high-purity water or an alkaline aqueous solution of sodium hydroxide with a pH of 9 ≤ pH ≤ 10.

[0020] Preferably, in step four, the specific method for rinsing the grating element after wet shallow etching includes:

[0021] S41. The grating element is fully immersed in a stainless steel tank containing high-purity water with a resistivity ≥15MΩ·cm. The water temperature is 50℃. The bottom of the tank has an ultrasonic plate. During the cleaning process, the frequency of the ultrasonic plate changes sequentially from 28kHz, 40kHz, 80kHz, 108kHz to 120kHz, with each frequency lasting for 3 minutes.

[0022] S42. Immerse the grating element completely in a stainless steel tank containing high-purity water with a resistivity ≥15MΩ·cm. The water temperature is 50℃. The bottom of the tank has an ultrasonic transducer plate. During the cleaning process, the ultrasonic transducer plate has a frequency of 750kHz and a duration of 10 minutes.

[0023] Preferably, in step five, the specific method for slowly lifting the rinsed grating element includes: fully immersing the grating element in a stainless steel tank containing high-purity water with a resistivity ≥15MΩ·cm, and controlling the water temperature at 20℃; and lifting the grating element out of the water at a speed of 50mm / min.

[0024] The present invention has at least the following beneficial effects: The method of improving the laser damage resistance of grating elements by wet shallow etching provided by the present invention can effectively remove contamination or defects on the surface or subsurface of the grating element, significantly reduce the absorption of laser energy by the grating element, thereby improving the laser damage resistance of the grating element, extending the service life of the grating element, and reducing the cost of using the grating element.

[0025] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of microscopic defects on the surface of a grating element.

[0027] Figure 2 This is a flowchart illustrating the method for improving the laser damage resistance of grating elements using wet etching, as provided by the present invention.

[0028] Figure 3 This is a schematic diagram comparing the shallow etching process on the surface of the grating element before and after an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram comparing the laser damage resistance of the grating element before and after wet shallow etching in an embodiment of the present invention. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0031] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0032] Example

[0033] like Figure 2 As shown, this embodiment provides a method for improving the laser damage resistance of grating elements using wet shallow etching, including the following steps:

[0034] Step 1: Spray cleaning the grating element to remove particulate contaminants adhering to its surface. Specific methods include:

[0035] S11. Place the grating element in the middle of an array of nozzles with a jet velocity ≥2m / s. The grating element is placed vertically, and the jet direction is towards the surface of the grating element, at a 30° angle downwards to the surface of the grating element. The jet water temperature is 50℃, and the spraying time is 5 minutes. The cleaning solution used for spray cleaning is high-purity water with a resistivity ≥15MΩ·cm.

[0036] S12. The grating element is fully immersed in a stainless steel tank containing high-purity water with a resistivity ≥15MΩ·cm. The water temperature is 50℃. The bottom of the tank has an ultrasonic plate. During the cleaning process, the frequency of the ultrasonic plate changes sequentially from 28kHz, 40kHz, 80kHz, 108kHz to 120kHz, with each frequency lasting for 3 minutes.

[0037] Step 2: After spray cleaning, the grating elements are cleaned with alkaline solution to remove organic contaminants from their surface. The specific method includes: immersing the grating elements completely in a stainless steel tank containing a 5% sodium hydroxide solution at a temperature of 35°C. The tank has an ultrasonic transducer at the bottom. During the cleaning process, the ultrasonic transducer frequency is changed sequentially from 28kHz, 40kHz, 80kHz, 108kHz to 120kHz, with each frequency lasting for 5 minutes.

[0038] Step 3: Perform wet shallow etching on the grating element after alkaline cleaning to remove subsurface defects. The specific method includes: immersing the grating element in a 0.5% hydrofluoric acid solution in a polytetrafluoroethylene tank; placing an ultrasonic transducer at the bottom of the tank; during the shallow etching process, the ultrasonic transducer frequency is 750kHz, the duration is 10 minutes, the temperature of the hydrofluoric acid solution is controlled at 30℃, and the shallow etching depth is 100nm.

[0039] Step 4: Rinse the grating element after wet shallow etching to remove residual etching solution and etching products. Specific methods include:

[0040] S41. The grating element is fully immersed in a stainless steel tank containing high-purity water with a resistivity ≥15MΩ·cm. The water temperature is 50℃. The bottom of the tank has an ultrasonic plate. During the cleaning process, the frequency of the ultrasonic plate changes sequentially from 28kHz, 40kHz, 80kHz, 108kHz to 120kHz, with each frequency lasting for 3 minutes.

[0041] S42. The grating element is fully immersed in a stainless steel tank containing high-purity water with a resistivity ≥15MΩ·cm. The water temperature is 50℃. The bottom of the tank has an ultrasonic plate. During the cleaning process, the ultrasonic plate frequency is 750kHz and the duration is 10 minutes.

[0042] Step 5: Slowly lift the rinsed grating element. The specific method includes: fully immersing the grating element in a stainless steel tank containing high-purity water with a resistivity ≥15MΩ·cm, and controlling the water temperature at 20℃; lifting the grating element out of the water at a speed of 50mm / min.

[0043] After the grating element undergoes spray rinsing, alkaline cleaning, wet shallow etching, rinsing, and slow lifting surface treatment, as follows: Figure 3As shown, the surface changes from an initial state with surface or subsurface contamination or defects to a state with neither surface nor subsurface contamination or defects. This significantly improves the laser damage resistance of the grating element after wet shallow etching, greatly extending its service life and thus significantly reducing its cost. Simultaneously, since only the surface of the grating is shallowly etched, the depth of the shallow etching is a negligible change relative to the grating structure depth, allowing the function and performance of the grating element to be maintained, or ensuring that the impact of the minor change is acceptable.

[0044] In this embodiment, the grating element has dimensions of 430mm × 430mm × 10mm. Several test points were selected on the surface of the grating element before and after wet shallow etching to test the laser damage resistance threshold of these test points. The results are as follows: Figure 4 ,from Figure 4 It can be seen that the average laser damage resistance threshold before wet shallow engraving is 4.60 J / cm. 2 The average laser damage resistance threshold after wet shallow etching was 6.91 J / cm. 2 The increase exceeded 50%.

[0045] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0046] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for improving the laser damage resistance of grating elements using wet shallow etching, characterized in that, Includes the following steps: Step 1: Spray cleaning the grating elements. Specific methods include: S11. Place the grating element in the middle of an array of nozzles with a jet velocity ≥2 m / s. The grating element is placed vertically, and the jet direction is towards the surface of the grating element, angled downwards at a 30° angle to the surface of the grating element. The jet water temperature is 50℃, and the spraying time is 5 minutes. S12. The grating element is fully immersed in a stainless steel tank containing high-purity water with a resistivity ≥15 MΩ·cm. The water temperature is 50℃. The bottom of the tank has an ultrasonic plate. During the cleaning process, the frequency of the ultrasonic plate changes sequentially from 28 kHz, 40 kHz, 80 kHz, 108 kHz to 120 kHz, with each frequency lasting for 3 minutes. Step 2: Clean the grating elements with alkaline solution after spray cleaning; Step 3: Perform wet shallow etching on the grating element after alkaline cleaning. Specific methods include: The grating element was immersed in a 0.5% hydrofluoric acid solution in a polytetrafluoroethylene tank. An ultrasonic transducer was placed at the bottom of the tank. During the shallow etching process, the frequency of the ultrasonic transducer was 750 kHz, the duration was 10 minutes, the temperature of the hydrofluoric acid solution was controlled at 30 ℃, and the shallow etching depth was 100 nm. Step 4: Rinse the grating elements after wet shallow etching; Step 5: Slowly lift the rinsed grating element. Specific methods include: The grating element is fully immersed in a stainless steel tank containing high-purity water with a resistivity ≥15 MΩ·cm, and the water temperature is controlled at 20℃; the grating element is then lifted out of the water at a speed of 50 mm / min. In step one, the cleaning solution used for spray cleaning of the grating element is one of the following: high-purity water with a resistivity ≥15 MΩ·cm, 25wt% ethanol organic reagent solution, diluted 5wt% hydrochloric acid cleaning solution, or 5wt% sodium hydroxide alkaline cleaning solution. In step three, the etching solution used for wet shallow etching of the grating element after alkaline cleaning includes one of hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid, sodium hydroxide, or potassium hydroxide. In step two, the alkaline solution used for alkaline cleaning of the grating element after spray cleaning is a sodium hydroxide or potassium hydroxide solution, or a mixed solution of sodium hydroxide and potassium hydroxide. In step two, the specific method for alkaline cleaning of the grating element after spray cleaning includes: immersing the grating element completely in a stainless steel tank containing a 5% sodium hydroxide solution at a temperature of 35°C; the bottom of the tank has an ultrasonic transducer plate; during the cleaning process, the frequency of the ultrasonic transducer plate changes sequentially from 28 kHz, 40 kHz, 80 kHz, 108 kHz to 120 kHz, with each frequency lasting for 5 minutes; In step four, the rinsing solution used to rinse the grating element after wet shallow etching is high-purity water or an alkaline sodium hydroxide aqueous solution with pH 9 ≤ 10. In step four, the specific method for rinsing the grating element after wet shallow etching includes: S41. The grating element is fully immersed in a stainless steel tank containing high-purity water with a resistivity ≥15 MΩ·cm. The water temperature is 50℃. The bottom of the tank has an ultrasonic plate. During the cleaning process, the frequency of the ultrasonic plate changes sequentially from 28 kHz, 40 kHz, 80 kHz, 108 kHz to 120 kHz, with each frequency lasting for 3 minutes. S42. Immerse the grating element completely in a stainless steel tank containing high-purity water with a resistivity ≥15 MΩ·cm. The water temperature is 50 ℃. The bottom of the tank has an ultrasonic plate. During the cleaning process, the ultrasonic plate frequency is 750 kHz and the duration is 10 minutes.

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