Method for prolonging service life of laser

Abstract

The invention relates to the technical field of lasers, and discloses a method for prolonging the service life of a laser, which comprises the following steps of: carrying out illumination test on N nonlinear crystals, and recording the time of generating a gray track effect by the N nonlinear crystals. And calibrating the minimum value in the time for generating the gray track effect as the critical time. A transition time is then calculated using the critical time. The end face of a nonlinear crystal used by the laser is divided into a plurality of light spot areas which are the same in area and are not overlapped, the area of the light spot areas is larger than the actual light spot area, and the shapes of the light spot areas can contain the light spot shape. All the light spot areas are labeled, and each label is not repeated. Finally, in the operation process of the laser, the position of the light spot on the end face of the nonlinear crystal is moved once every conversion time. And the light spots circularly move in the plurality of light spot areas. According to the method, thermal stress cracks, phase change or melting caused by local energy absorption of the nonlinear crystal under ultraviolet irradiation are avoided, and the service life of the laser is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of lasers, and in particular to a method for extending the life of a laser. Background Art

[0002] Ultraviolet lasers are widely used in industries, medical treatment, military, aerospace, scientific research and other fields due to their advantages such as short wavelength, small spot size, and high peak power. Since both laser crystals and frequency conversion crystals have certain damage thresholds, especially ultraviolet frequency conversion crystals are prone to being damaged by ultraviolet light, laser crystals are easily damaged during use. Therefore, ultraviolet lasers need to frequently replace crystals, and their service life is limited, and they often cannot meet the requirements of long-term stable operation. Summary of the Invention

[0003] Based on the above, the object of the present invention is to provide a method for extending the life of a laser to extend the life of the laser.

[0004] To achieve the above object, the present invention adopts the following technical solutions: A method for extending the life of a laser, comprising the following steps: S1. Perform a light irradiation test on N non-linear crystals, where N is a positive integer greater than 1, and record the time when the N non-linear crystals generate a gray trace effect; S2. Calibrate the minimum value among the times when all the non-linear crystals generate a gray trace effect as the critical time; S3. Calculate a conversion time using the critical time, and the conversion time is less than or equal to the critical time; S4. Divide the end face of the non-linear crystal used in the laser into a plurality of light spot regions with the same area and non-overlapping, the area of the light spot region is larger than the actual light spot area, and the shape of the light spot region can contain the light spot shape; S5. Number all the light spot regions, and each number is not repeated, denoted as a1, a2,..., a n , where n is a positive integer greater than or equal to 1; S6. During the operation of the laser, move the position of the light spot on the end face of the non-linear crystal every conversion time; the light spot moves cyclically within a plurality of the light spot regions, and gradually moves from the a1 light spot region to a n light spot region within each cycle.

[0005] As a preferred solution of a method for extending the life of a laser, the N non-linear crystals include non-linear crystals of one material or non-linear crystals of multiple different materials.

[0006] As a preferred solution of a method for extending the life of a laser, multiple light spot regions of the same size are divided on the end faces of each nonlinear crystal, and each region is subjected to a light irradiation test, and the time when the gray trace effect occurs in each region is recorded.

[0007] As a preferred solution of a method for extending the life of a laser, it further includes the following sub-steps: S6-1. During the operation of the laser, the output power of the laser is detected in real time. If it is detected that the output power of the laser decreases, the current light spot region a x is recorded in the blacklist, and the light spot is immediately moved to the next light spot region a x+1 or moved to a1, where 1 ≤ x ≤ n; S6-2. Cancel the label a of the light spot region in the blacklist x ; S6-3. Re-label the a x+1 light spot region, a x+2 light spot region,..., a n light spot region as a x light spot region, a x+1 light spot region,..., a n-1 light spot region.

[0008] The beneficial effects of the present invention are as follows: The present invention first performs a light irradiation test on N nonlinear crystals, where N is a positive integer greater than 1, and records the time when the gray trace effect occurs in the N nonlinear crystals. The minimum value among the times when all the nonlinear crystals produce the gray trace effect is calibrated as the critical time. Then, the conversion time is calculated using the critical time, and the conversion time is less than or equal to the critical time. Further, multiple light spot regions with the same area and non-overlapping are divided on the end faces of the nonlinear crystals used in the laser. The area of the light spot region is larger than the actual light spot area, and the shape of the light spot region can contain the light spot shape. All the light spot regions are labeled, and each label is not repeated, denoted as a1, a2,..., a n , where n is a positive integer greater than or equal to 1. Finally, during the operation of the laser, the position of the light spot on the end face of the nonlinear crystal is moved every conversion time. The light spot moves cyclically within multiple light spot regions, and gradually moves from the a1 light spot region to the a n light spot region within each cycle. This method avoids local absorption of energy by the nonlinear crystal under long-term and high-power-density ultraviolet light irradiation, which may cause thermal stress cracks, phase changes, or melting, improves the service time of the nonlinear crystal, and thus extends the service life of the laser. Description of the Drawings

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the description of the embodiments of the present invention. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on the content of the embodiments of the present invention and these accompanying drawings.

[0010] Figure 1 is a flowchart of the method for extending the life of a laser provided by the specific embodiment of the present invention; Figure 2 is a schematic diagram of the optical path of the laser provided by the specific embodiment of the present invention; Figure 3 is a detailed flowchart of the method for extending the life of a laser provided by the specific embodiment of the present invention.

[0011] In the figure: 100 - resonator; 200 - power detection module; 1 - first optical wedge; 2 - second optical wedge; 3 - third optical wedge; 4 - fourth optical wedge; 5 - nonlinear crystal. Specific Embodiment

[0012] To make the technical problems solved by the present invention, the technical solutions adopted, and the achieved technical effects clearer, the following will further describe the technical solutions of the embodiments of the present invention in detail with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0013] As Figure 1 shown, this embodiment provides a method for extending the life of a laser, including the following steps: S1. Perform light irradiation tests on N nonlinear crystals, where N is a positive integer greater than 1, and record the time when the N nonlinear crystals produce the gray trace effect; S2. Calibrate the minimum value among the times when all nonlinear crystals produce the gray trace effect as the critical time; S3. Calculate the conversion time using the critical time, and the conversion time is less than or equal to the critical time; S4. Divide the end face of the nonlinear crystal used in the laser into multiple non - overlapping light spot regions with the same area. The area of the light spot region is larger than the actual light spot area, and the shape of the light spot region can contain the shape of the light spot; S5. Number all the light spot regions, and each number is not repeated, denoted as a1, a2,..., a n , where n is a positive integer greater than or equal to 1; S6. During the operation of the laser, the position of the light spot on the end face of the nonlinear crystal is moved every conversion time; the light spot moves cyclically within multiple light spot regions, and gradually moves from the a1 light spot region to the a n light spot region within each cycle.

[0014] This method avoids the local absorption of energy by the nonlinear crystal under long-term ultraviolet light irradiation with high power density, which may cause thermal stress cracks, phase transformation, or melting, improves the service time of the nonlinear crystal, and thus extends the service life of the laser.

[0015] Specifically, referring to Figure 2 , in this embodiment, the laser includes a resonator 100 and a laser power detection module 200. The resonator 100 includes two sets of optical wedges composed of the first optical wedge 1, the second optical wedge 2, the third optical wedge 3, and the fourth optical wedge 4. The first optical wedge 1 and the second optical wedge 2 form one set, and the third optical wedge 3 and the fourth optical wedge 4 form one set. The two sets of optical wedges are placed at an angle. One set of optical wedges is responsible for adjusting the horizontal movement of the light spot, and the other set of optical wedges is responsible for adjusting the vertical movement of the light spot. The two sets of optical wedges cooperate to achieve the dot matrix movement of the light spot on the end face of the nonlinear crystal 5.

[0016] The main causes of damage to the nonlinear crystal in the ultraviolet laser include thermal damage and photochemical damage. Under the irradiation of ultraviolet light with high power density, the local absorption of energy by the nonlinear crystal leads to a temperature rise. If the heat cannot be dissipated in time, it will cause thermal stress cracks, phase transformation, or melting. At the same time, due to the high energy of ultraviolet photons, it is easy to excite internal defects or impurities in the nonlinear crystal, resulting in an increase in the local absorption coefficient, that is, the gray trace effect. As the irradiation time increases, the region with enhanced absorption will further heat up, eventually leading to permanent damage to the crystal.

[0017] In this embodiment, the light irradiation test is first performed on N nonlinear crystals, where N is a positive integer greater than 1, and the time when the gray trace effect occurs in the N nonlinear crystals is recorded. In this embodiment, N is 10, that is, 10 nonlinear crystals are tested. In this embodiment, the 10 nonlinear crystals are nonlinear crystals of various different materials, including but not limited to lithium triborate crystal, cesium lithium triborate crystal, potassium dihydrogen phosphate crystal, etc. It should be additionally noted that the 10 nonlinear crystals can also be the same crystal in other embodiments.

[0018] The minimum value of the time when the gray trace effect occurs in the 10 nonlinear crystals is calibrated as the critical time. In this embodiment, the critical time is 50 ms. Then, the conversion time is calculated using the critical time, and the conversion time is less than or equal to the critical time. In this embodiment, in order to ensure that the nonlinear crystal is not damaged, the conversion time is half of the critical time, that is, 25 ms.

[0019] Divide the end face of the non-linear crystal 5 used in the laser into multiple spot regions with the same area and no overlap. The area of the spot region is larger than the actual spot area, and the shape of the spot region can contain the shape of the spot. In this embodiment, the non-linear crystal 5 uses a 6mm * 6mm LBO crystal, and the diameter of the laser spot is about 1mm. The end face is divided into 16 rectangular regions of the same size. The area of the rectangular region is larger than the actual spot area, and the shape of the rectangular region can contain the shape of the spot. Label the 16 rectangular regions, and each label is not repeated, denoted as a1, a2,..., a 16 .

[0020] It should be noted that the arrangement of a1, a2,..., a 16 may be arranged in sequence, in a matrix, symmetrically, or completely irregularly according to different usage scenarios. In this embodiment, an example is given in the form of a matrix arrangement.

[0021] During the operation of the laser, move the position of the spot on the end face of the non-linear crystal 5 every 25 ms, which can not only ensure that a point will not be damaged due to long-term irradiation, but also ensure that each point has sufficient heat dissipation time and will not cause thermal accumulation. The spot moves cyclically within multiple spot regions, and gradually moves from the a1 spot region to a 16 spot region during each cycle.

[0022] In this application example, when the first optical wedge 1 is fixed and the second optical wedge 2 moves forward, the spot gradually moves to the right; when the second optical wedge 2 moves backward, the spot moves to the left. Similarly, when the third optical wedge 3 is fixed and the fourth optical wedge 4 moves forward, the spot gradually moves up; when the fourth optical wedge 4 moves backward, the spot gradually moves down. Therefore, by controlling the movement of the second optical wedge 2 and the fourth optical wedge 4, the spot can be scanned at 16 positions on the end face of the non-linear crystal 5.

[0023] Referring to Figure 3 , step S6 further includes the following sub-steps: S6-1. During the operation of the laser, the power detection module 200 continuously detects the output power of the laser. If it detects that the output power of the laser decreases, then mark the current spot region a x in the blacklist, and immediately move the spot to the next spot region a x+1 or move it to a1, where 1 ≤ x ≤ n; For example, in this embodiment, when the laser detects a decrease in the output power in the a3 region among the 16 spot regions, mark the current spot region a3 in the blacklist, and immediately move the spot to the next spot region a4; S6-2. Cancel the label a3 of the spot region in the blacklist.

[0024] S6-3, the a4 spot area, the a5 spot area, ..., a 16 The spot areas are re-labeled as a3 spot area, a4 spot area, ..., a 15 Light spot area.

[0025] For example, when the optical device is in a of the 16 spot area 16 Area detection: When the output power is reduced, the current spot area a 16 Record it in the blacklist and immediately move the light spot to the next light spot area a1.

[0026] Cancel the label a of the spot area in the blacklist 16 .

[0027] S6-3, the a1 spot area, the a2 spot area, ..., a 15 The spot areas are re-labeled as a1 spot area, a2 spot area, ..., a 15 Light spot area.

[0028] According to the content recorded in this method, after re-numbering, the next time the light spot moves cyclically in multiple light spot areas, gradually moving from the a1 light spot area to the a1 light spot area in each cycle. 15 The spot area will automatically skip the unlabeled area to improve work efficiency.

[0029] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

[0030] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A method for extending the lifespan of a laser, characterized in that, Including the following steps: S1. Conduct light irradiation tests on N nonlinear crystals, where N is a positive integer greater than 1, and record the time when the N nonlinear crystals produce the gray trace effect; S2. Calibrate the minimum value among the times when all the nonlinear crystals produce the gray trace effect as the critical time; S3. Calculate the conversion time using the critical time, and the conversion time is less than or equal to the critical time; S4. Divide the end face of the nonlinear crystal used in the laser into multiple spot regions with the same area and no overlap, the area of the spot region is larger than the actual spot area, and the shape of the spot region can contain the spot shape; S5. Label all the spot regions, with each label being non-repeating, denoted as a1, a2, ..., a n , where n is a positive integer greater than or equal to 1; S6. During the operation of the laser, move the position of the light spot on the end face of the nonlinear crystal every said conversion time; the light spot moves cyclically within a plurality of said light spot regions, and gradually moves from the a1 light spot region to the a n light spot region within each cycle.

2. The method for extending the life of a laser according to claim 1, wherein The N nonlinear crystals include nonlinear crystals of one material or nonlinear crystals of multiple different materials.

3. The method for extending the lifespan of a laser according to claim 1, characterized in that, Divide the end face of each nonlinear crystal into multiple spot regions of the same size, conduct a light irradiation test on each region, and record the time when each region produces the gray trace effect.

4. The method for prolonging the lifespan of a laser according to claim 1, characterized in that It also includes the following sub-steps: S6-1. During the operation of the laser, the output power of the laser is detected in real time. If it is detected that the output power of the laser decreases, the current spot area a x is recorded in the blacklist, and the spot is immediately moved to the next spot area a x+1 or moved to a1, where 1 ≤ x ≤ n; S6-2. Cancel the label a of the light spot area in the blacklist x ; S6-3. Rename the a x+1 light spot regions, a x+2 light spot regions,..., a n light spot regions as a x light spot regions, a x+1 light spot regions,..., a n-1 light spot regions.

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