High power laser diameter measuring device

Abstract

The present disclosure provides a high-power laser diameter measuring device, wherein a first reflector and a second reflector are respectively arranged on the optical path of the high-power laser beam to be measured incident into a detector, the portion of the laser beam blocked by the first reflector is reflected by the first reflector to the first collector, and the portion of the laser beam blocked by the second reflector is reflected by the second reflector to the second collector; the first reflector and the second reflector are both mounted on a first bracket, and the first bracket is integrated and mounted on a displacement stage group consisting of a first displacement stage and a second displacement stage through a connecting plate; the first telecentric lens, the first image sensor, the second telecentric lens and the second image sensor are respectively used to observe the first reflector and the second reflector in real time. The high-power laser diameter measuring device proposed in the present disclosure can reduce the source of diameter measurement error and improve measurement accuracy, can be used for direct measurement of laser diameter, and can also be used as a metrology standard device to calibrate other high-power laser spot analyzers.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical measurement, and in particular to a high-power laser diameter measurement device. Background Art

[0002] Laser spot diameter is one of the main indicators of lasers. Especially in laser processing related fields, such as laser brazing, cladding, quenching, cutting, cleaning, adjustment, additive manufacturing and other applications, the measurement and control of the laser spot diameter of high-power lasers is an important factor affecting the success of the process.

[0003] Accurate measurement of high-power laser spots requires reliable error source assessment and effective traceability assurance. Using CCD / CMOS image sensors to image the laser diameter is a common method for measuring high-power laser diameters. However, since the photosensitive elements of image sensors are limited by damage thresholds, saturation thresholds, etc., when measuring the diameter of high-power lasers, the beam must first be attenuated using means such as a spectroscope. For lasers with powers above kilowatts, ten thousand watts, or even hundreds of thousands of watts, attenuation often requires more than three times to reach the light intensity allowed by the image sensor. In addition, due to the limited size of the image sensor array, for laser beams with larger diameters, similar transformations must be performed through beam shrinking and other means to obtain a low-intensity beam similar to the original beam, which is finally incident on the image sensor for measurement.

[0004] In the above process, every time the laser beam passes through an optical component, it will be distorted to varying degrees due to reasons such as interface shape, interface reflectivity, medium refractive index, lattice arrangement, dust, etc. In addition, as the laser power continues to increase, the errors from the above sources will be further amplified. At the same time, other characteristic changes caused by heating of the component will further produce additional errors that are difficult to accurately estimate, ultimately making the measurement results unreliable. Summary of the invention

[0005] In view of this, the main purpose of the present disclosure is to provide a high-power laser diameter measurement device, aiming to solve the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above-mentioned purpose, the present disclosure provides a high-power laser diameter measuring device, including: a first reflector 1, a second reflector 2, a first bracket 3, a connecting plate 4, a first telecentric lens 5, a second telecentric lens 5', a first image sensor 6, a second image sensor 6', a second bracket 7, a first displacement stage 8, a second displacement stage 9, a detector 11, a first collector 12 and a second collector 13, wherein:

[0007] The first reflector 1 and the second reflector 2 are respectively arranged on the optical path of the high-power laser beam 14 to be measured incident into the detector 11, the portion of the laser beam 14 blocked by the first reflector 1 is reflected by the first reflector 1 to the first collector 12, and the portion of the laser beam 14 blocked by the second reflector 2 is reflected by the second reflector 2 to the second collector 13;

[0008] The first reflector 1 and the second reflector 2 are both mounted on the first bracket 3, and the first bracket 3 is integrally mounted on the displacement stage group consisting of the first displacement stage 8 and the second displacement stage 9 through the connecting plate 4;

[0009] The first telecentric lens 5, the first image sensor 6, the second telecentric lens 5' and the second image sensor 6' are all installed on the second bracket 7, and are used to observe the first reflector 1 and the second reflector 2 in real time, and correct the positions of the first reflector 1 and the second reflector 2 through edge detection algorithm feedback.

[0010] In the above scheme, the angle between the normal of the reflection surface of the first reflector 1 and the normal of the reflection surface of the second reflector 2 is 60°, the movement axis of the first reflector 1, the movement axis 2 of the second reflector and the main axis of the laser beam 14 are orthogonal to each other, and the movement axis of the first reflector 1 and the normal of the reflection surface of the first reflector 1 form an angle of 45°, and the movement axis of the second reflector 2 and the normal of the reflection surface of the second reflector 2 form an angle of 45°.

[0011] In the above scheme, the first reflector 1 and the second reflector 2 are respectively driven by the translation stage group and scanned along the orthogonal axis, and a scanning measurement of a certain cross section of the laser beam 14 is achieved by gradually blocking the beam.

[0012] In the above scheme, the first translation stage 8 and the second translation stage 9 are combined with each other to form a translation stage group with orthogonal two-axis (x, y) scanning and displacement functions. When the first reflector 1 and the second reflector 2 scan along the orthogonal x-axis and y-axis, they move from completely not blocking the laser beam 14 to completely blocking the laser beam 14, thereby completing the scanning measurement of a certain cross-section of the laser beam 14 along the x or y direction.

[0013] In the above scheme, the device also includes a third translation stage 10, which is arranged in the z-axis direction orthogonal to both the x-axis and the y-axis. The third translation stage 10 is combined with the first translation stage 8 and the second translation stage 9 to form a translation stage group with orthogonal three-axis (x, y, z) scanning and displacement function. When the first reflector 1 and the second reflector 2 scan along the orthogonal x-axis, y-axis and z-axis, they move from completely not blocking the laser beam 14 to completely blocking the laser beam 14, thereby completing the scanning measurement of a certain cross section of the laser beam 14 along the x, y or z direction.

[0014] In the above solution, the reflective surfaces of the first reflector 1 and the second reflector 2, as well as the edges that cut into the laser beam 14, all have a high reflectivity of 95% to 99.999%, thereby reducing the heat received by themselves. Optionally, the reflective surfaces of the first reflector 1 and the second reflector 2, as well as the edges that cut into the laser beam 14, are polished and coated.

[0015] In the above solution, the first reflector 1 and the second reflector 2 have a liquid cooling structure inside, or the first reflector 1 and the second reflector 2 are simultaneously cooled by high-pressure air cooling facing the reflecting surface. Optionally, the liquid cooling structure includes fins 21, a liquid cooling passage 22 and a sealing structure 23.

[0016] In the above scheme, the first telecentric lens 5 and the second telecentric lens 5' are both low-distortion telecentric lenses. The main optical axes of the first telecentric lens 5 and the first image sensor 6 are perpendicular to the reflection surface of the first reflector 1. The first image sensor 6 itself or after adding a filter does not respond to the wavelength of the laser beam 14, so as to avoid the scattered light of the strong laser from damaging the first image sensor 6; the main optical axes of the second telecentric lens 5' and the second image sensor 6' are perpendicular to the reflection surface of the second reflector 2. The second image sensor 6' itself or after adding a filter does not respond to the wavelength of the laser beam 14, so as to avoid the scattered light of the strong laser from damaging the second image sensor 6'.

[0017] In the above scheme, the first collector 12 is used to collect and terminate the laser reflected by the first reflector 1 to prevent it from being reflected, refracted, and scattered to other uncontrollable areas, causing damage to personnel, instruments and equipment; the second collector 13 is used to collect and terminate the laser reflected by the second reflector 2 to prevent it from being reflected, refracted, and scattered to other uncontrollable areas, causing damage to personnel, instruments and equipment; the first collector 12 and the second collector 13 both have a liquid-cooled heat dissipation structure and are resistant to high-power laser damage.

[0018] In the above solution, the device also includes a protective cover, which is arranged outside the high-power laser spot diameter measuring device.

[0019] It can be seen from the above technical solutions that the high-power laser diameter measuring device provided by the present disclosure has at least the following beneficial effects compared with the prior art:

[0020] 1. Compared with the sampling measurement method, the high-power laser diameter measurement device proposed in the present disclosure does not need to perform sampling transformation processing such as attenuation and beam reduction on the high-power laser, which greatly simplifies the structure that is in direct contact with the high-power laser during the measurement process and reduces the source of measurement errors. In the device, only the first reflector 1, the second reflector 2 and the detector 11 are in direct contact with the high-power laser and produce related measurement errors. Among them, the detector 11 is a dedicated high-power laser power meter, and the error is known and can be accurately traced and corrected. Therefore, according to the measurement principle, the additional error caused by the high-power effect of the laser only comes from the deformation and displacement of the first reflector 1 and the second reflector 2, and the overall error is easier to control and evaluate.

[0021] 2. The high-power laser diameter measurement device proposed in the present invention can accurately obtain the deformation and displacement of the first reflector 1 and the second reflector 2 through low-distortion imaging and edge detection algorithms, thereby correcting the additional errors caused by the high-power effect of the laser, forming a closed-loop control of the key error source, and the traceability chain is clear and unambiguous, thereby improving the accuracy and reliability of the measurement device.

[0022] 3. The high-power laser diameter measurement device proposed in the present disclosure adopts a dual orthogonal symmetrical configuration in structure, with a reasonable optical path layout and compact space. While ensuring the distortion-free positive imaging of the reflector, it will not block the incident laser, and the incident laser can be reflected in two directions perpendicular to the incident optical axis, and safely collected by the high-power laser collector that takes up a large space, avoiding the high-power laser from being reflected back to the laser window or reflected and scattered to other devices and personnel to cause damage. In addition, this configuration allows the main structure to fit more closely with the displacement platform, reducing the micro-deformation and displacement of the structure itself caused by stress torque, and is more conducive to the accurate and stable observation of the micro-deformation and displacement of the reflector. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0024] Figure 1 It is a schematic diagram of the three-dimensional structure of a high-power laser diameter measurement device according to an embodiment of the present disclosure.

[0025] Figure 2 Schematic cross-sectional view of a high-power laser diameter measurement device according to an embodiment of the present disclosure.

[0026] Figure 3 It is a perspective schematic diagram of key structural features of a reflector in a high-power laser diameter measurement device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0028] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0029] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0030] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0031] like Figure 1 and Figure 2 As shown, the present disclosure provides a high-power laser diameter measuring device, including: a first reflector 1, a second reflector 2, a first bracket 3, a connecting plate 4, a first telecentric lens 5, a second telecentric lens 5', a first image sensor 6, a second image sensor 6', a second bracket 7, a first displacement stage 8, a second displacement stage 9, a detector 11, a first collector 12 and a second collector 13. Furthermore, in order to prevent the scattered light of the strong laser from arbitrarily scattering and threatening the safety of the experimenter or other equipment, a protective cover is arranged outside the high-power laser diameter measuring device.

[0032] In the high-power laser diameter measuring device provided in the present disclosure, the first reflector 1 and the second reflector 2 are respectively arranged on the optical path of the high-power laser beam 14 to be measured that is incident on the detector 11. The part of the laser beam 14 blocked by the first reflector 1 is reflected by the first reflector 1 to the first collector 12, and the part of the laser beam 14 blocked by the second reflector 2 is reflected by the second reflector 2 to the second collector 13.

[0033] The first reflector 1 and the second reflector 2 are both mounted on the first bracket 3 , and the first bracket 3 is integrally mounted on the displacement stage group consisting of the first displacement stage 8 and the second displacement stage 9 through the connecting plate 4 .

[0034] The first telecentric lens 5, the first image sensor 6, the second telecentric lens 5' and the second image sensor 6' are all installed on the second bracket 7, and are used to observe the first reflector 1 and the second reflector 2 in real time, and correct the positions of the first reflector 1 and the second reflector 2 through edge detection algorithm feedback.

[0035] The first reflector 1 and the second reflector 2 are driven by a translation stage group consisting of a first translation stage 8 and a second translation stage 9 respectively, and scan along the orthogonal axis to achieve scanning measurement of a certain cross section of the laser beam 14 by gradually blocking the beam.

[0036] The angle between the normal of the reflection surface of the first reflector 1 and the normal of the reflection surface of the second reflector 2 is 60°, the movement axis of the first reflector 1, the movement axis of the second reflector and the main axis of the laser beam 14 are orthogonal to each other, and the movement axis of the first reflector 1 and the normal of the reflection surface of the first reflector 1 form an angle of 45°, and the movement axis of the second reflector 2 and the normal of the reflection surface of the second reflector 2 form an angle of 45°.

[0037] The first translation stage 8 and the second translation stage 9 are combined with each other to form a translation stage group with orthogonal two-axis (x, y) scanning and translation functions. When the first reflector 1 and the second reflector 2 scan along the orthogonal x-axis and y-axis, they move from completely not blocking the laser beam 14 to completely blocking the laser beam 14, thereby completing the scanning measurement of a certain cross-section of the laser beam 14 along the x or y direction.

[0038] The first reflector 1 is arranged on the optical path of the high-power laser beam 14 to be measured entering the detector 11. Figure 1 In the xyz coordinate system shown, the plane where the first reflector 1 is located has an angle of 45° with the xy plane and the yz plane, and is perpendicular to the xz plane. The first reflector 1 moves along the x-axis direction, from completely not blocking the laser beam 14 to completely blocking the laser beam 14, thereby completing the scanning measurement of a certain cross section of the laser beam 14 along the x-direction. The portion of the laser beam 14 blocked by the first reflector 1 is reflected by the first reflector 1 to the first collector 12, and the first collector 12 collects and stops the laser reflected by the first reflector 1 to prevent it from being reflected, refracted, and scattered to other uncontrollable areas, causing damage to personnel and equipment.

[0039] The second reflector 2 is arranged on the optical path of the high-power laser beam 14 to be measured entering the detector 11. Figure 1In the xyz coordinate system shown, the plane where the second reflector 2 is located has an angle of 45° with the xy plane and the xz plane, and is perpendicular to the yz plane. The second reflector 2 moves along the y-axis direction, from completely not blocking the laser beam 14 to completely blocking the laser beam 14, thereby completing the scanning measurement of a certain cross section of the laser beam 14 along the y direction. The portion of the laser beam 14 blocked by the second reflector 2 is reflected by the second reflector 2 to the second collector 13, and the second collector 13 collects and stops the laser reflected by the second reflector 2 to prevent it from being reflected, refracted, and scattered to other uncontrollable areas, causing damage to personnel and equipment.

[0040] like Figure 1 and Figure 2 As shown, when a certain cross section of the laser beam 14 is scanned and measured along the x or y direction, during the scanning process, the translation stage records the optical power value measured by the detector 11 each time it steps forward, and the difference between the power recorded in the previous step and the current recorded power is used as the optical power value of the light beam in the space blocked by the reflector during this step, and this value is recorded as P(x) or Q(y).

[0041] Specifically, during the scanning process, each time the first displacement stage 8 steps forward, the optical power value measured by the detector 11 is recorded, and the difference between the power recorded in the previous step and the current recorded power is used as the optical power value of the laser beam 14 in the space blocked by the first reflector 1 during this stepping process, and this value is recorded as P(x).

[0042] Similarly, each time the second translation stage 9 steps forward, the optical power value measured by the detector 11 is recorded, and the difference between the power recorded in the previous step and the current recorded power is used as the optical power value of the laser beam 14 in the space blocked by the second reflector 2 during this stepping process, and this value is recorded as Q(y).

[0043] According to the general definition of laser beam diameter, when the above-mentioned orthogonal scanning method is used for measurement, the calculation formula of the laser beam diameter d is as follows:

[0044]

[0045] Wherein, x is the x-axis coordinate corresponding to the scanning optical power P(x), and y is the y-axis coordinate corresponding to the scanning optical power Q(y). , ) is the center of gravity of the light spot, , Through the above measurement steps and calculations, the diameter measurement is completed.

[0046] In the high-power laser spot diameter measurement device provided by the present disclosure, the first displacement stage 8 and the second displacement stage 9 are used to perform orthogonal scanning motion. Further, when a one-dimensional third displacement stage 10 is added in the third orthogonal direction z, scanning can be performed in the third dimension to obtain multiple diameter slice measurement results along the beam propagation direction, thereby obtaining other transmission characteristics of the beam, which helps calculate the divergence angle, M 2 Parameters such as factors, this extension should also be considered as part of the present invention.

[0047] Specifically, the device also includes a third translation stage 10, which is arranged in the z-axis direction orthogonal to both the x-axis and the y-axis. The third translation stage 10 is combined with the first translation stage 8 and the second translation stage 9 to form a translation stage group with an orthogonal three-axis (x, y, z) scanning and displacement function. When the first reflector 1 and the second reflector 2 scan along the orthogonal x-axis, y-axis and z-axis, they move from completely not blocking the laser beam 14 to completely blocking the laser beam 14, thereby completing the scanning measurement of a certain cross section of the laser beam 14 along the x, y or z direction.

[0048] When performing three-dimensional scanning along the x, y or z direction, scan the x and y axes respectively at a fixed z-axis coordinate. Depending on the required resolution and measurement accuracy, the scanning interval can usually be 1 / 20~1 / 1000 of the expected diameter of the light spot. After the scanning in the x and y directions is completed, the diameter of the beam at the section where the z-axis fixed coordinate is located, as well as the one-dimensional intensity distribution along the x and y axes are obtained. Then, the x and y axis scanning sections are changed by the z-axis translation stage, and the previous step is repeated to obtain the beam diameter at the section at the next z-axis coordinate until the z-axis target area is scanned. According to the change law of the obtained spot diameter along the z-axis, the divergence angle, M 2 And other parameters.

[0049] During the scanning measurement process, the reflective surfaces of the first reflector 1 and the second reflector 2 are in direct contact with the high-power laser beam and are cut into by one side of the beam. Therefore, the reflective surfaces of the first reflector 1 and the second reflector 2, as well as the edges that cut into the laser beam 14, have a high reflectivity of 95% to 99.999% for the target laser to be measured, thereby reducing the heat received by themselves. Specifically, the reflective surfaces of the first reflector 1 and the second reflector 2, as well as the edges that cut into the laser beam 14, are polished and coated, wherein the coating is a high-reflective film such as a metal film or a dielectric film.

[0050] Optionally, the first reflector 1 and the second reflector 2 have a liquid cooling structure inside, such as Figure 3 As shown, the liquid cooling structure includes fins 21, liquid cooling passages 22 and sealing structures 23. Alternatively, the first reflector 1 and the second reflector 2 can also be cooled by high-pressure air cooling facing the reflective surface at the same time.

[0051] During measurement, the edge cuts into the light beam at a 90° right angle. When the edge itself also has a 90° right angle feature, it is more conducive to processing and improving the efficiency of the internal heat dissipation structure.

[0052] When the laser power is high and the spot is small, the deformation and displacement such as expansion of the edges of the first reflector 1 and the second reflector 2 constitute an important unknown error source of the measurement.

[0053] By observing the first reflector 1 in real time through the first telecentric lens 5 and the first image sensor 6, the deformation and displacement can be included in the traceability chain, so as to accurately estimate the diameter measurement error caused by the deformation and displacement, and compensate and correct it. Specifically, the main optical axis of the first telecentric lens 5 and the first image sensor 6 is perpendicular to the reflection surface of the first reflector 1. The first image sensor 6 itself or after adding a filter does not respond to the wavelength of the laser beam 14, so as to avoid the scattered light of the strong laser from damaging the first image sensor 6; the first telecentric lens 5 adopts a low-distortion telecentric lens, which has the characteristics of low-distortion imaging, and is conducive to accurate observation of the deformation and displacement of the entire first reflector 1; the geometric deformation of the edge of the first reflector 1 can be quantitatively fed back by the edge detection algorithm to correct the position of the displacement stage, so that each step spacing is accurate and constant, and is not affected by the blade deformation, or the diameter error is corrected by numerically compensating the diameter calculation formula.

[0054] Similarly, by real-time observation of the second reflector 2 through the second telecentric lens 5' and the second image sensor 6', the deformation and displacement can be included in the traceability chain, so as to accurately estimate the diameter measurement error caused by the deformation and displacement. Specifically, the main optical axis of the second telecentric lens 5' and the second image sensor 6' is perpendicular to the reflection surface of the second reflector 2. The second image sensor 6' itself or after adding a filter does not respond to the wavelength of the laser beam 14, so as to avoid the scattered light of the strong laser from damaging the second image sensor 6'. The second telecentric lens 5' adopts a low-distortion telecentric lens, which has the characteristics of low-distortion imaging, which is conducive to accurate observation of the deformation and displacement of the entire second reflector 2; the geometric deformation of the edge of the second reflector 2 can be quantitatively fed back by the edge detection algorithm to correct the position of the displacement stage, so that each step spacing is accurate and constant, and is not affected by the deformation of the blade, or the diameter error is corrected by numerical compensation of the diameter calculation formula.

[0055] In the present disclosure, the algorithm processing of the image formed by the first reflector 1 or the second reflector 2 is aimed at obtaining the deformation and displacement of the edge of the first reflector 1 or the second reflector 2 cutting into the laser beam, and its edge detection algorithm includes but is not limited to the Sobel algorithm, the Canny algorithm, and the deep learning algorithm. With an image sensor with good resolution, a lens with good modulation transfer function, and a short-wave illumination light source, the sub-micron deformation and displacement observation of the edge of the first reflector 1 or the second reflector 2 can be realized.

[0056] The detector 11 is a special laser power detector covering a high power range. The detector 11 can adopt a photobarometry or calorimetric sensing principle. The detector 11 itself has good linearity. When the laser beam 14 is gradually blocked and scanned, the error in the measurement result of the relative size of the optical power only constitutes a part of the uncertainty of the special laser power detector, that is, it does not exceed the power measurement uncertainty of the detector 11.

[0057] The first reflector 1 and the second reflector 2 are mounted on the first bracket 3, the first image sensor 6 is mounted on the first telecentric lens 5, the first telecentric lens 5 is mounted on the second bracket 7, and the first reflector 1 and the second reflector 2 are integrated and mounted on the displacement stage group. During the measurement and scanning process, especially when the light spot is small, the displacement error of the first reflector 1 and the second reflector 2 is sensitive. The first bracket 3 and the second bracket 7 are integrated and mounted on the first displacement stage 8 and the second displacement stage 9 through the connecting plate 4, wherein the first bracket 3, the second bracket 7 and the connecting plate 4 are made of high-hardness lightweight metal and non-metallic materials (such as aviation aluminum, POM steel) to reduce stress deformation and displacement and deformation and displacement caused by scanning vibration.

[0058] The first collector 12 is used to collect and terminate the laser reflected by the first reflector 1 to prevent it from being reflected, refracted, or scattered to other uncontrollable areas, thereby preventing damage to personnel, equipment, and other devices. The first collector 12 itself has efficient (air-cooled, liquid-cooled) heat dissipation characteristics and is resistant to damage from high-power lasers.

[0059] The second collector 13 is used to collect and terminate the laser reflected by the second reflector 2 to prevent it from being reflected, refracted, and scattered to other uncontrollable areas, thereby preventing damage to personnel, instruments, and equipment. The second collector 13 itself has efficient (air-cooled, liquid-cooled) heat dissipation characteristics and is resistant to damage from high-power lasers.

[0060] Specifically, the first collector 12 and the second collector 13 both have a liquid cooling structure and are resistant to damage by high-power lasers.

[0061] When performing a two-dimensional scan of the beam diameter, two collectors, namely a first collector 12 and a second collector 13, may be arranged along orthogonal optical paths. The configuration of the present invention reserves sufficient placement space for the collectors.

[0062] When a high-power laser beam with good beam quality and stable spatiotemporal characteristics is used as the reference laser beam to be measured, the laser diameter device described in the present invention has controllable errors, a complete closed-loop traceability chain, and extremely small measurement errors. Therefore, it can also be used as a metrology standard device to calibrate other beam quality analyzers and spot analyzers suitable for high-power lasers.

[0063] To summarize, the high-power laser diameter measurement device proposed in the present invention utilizes the first reflector and the second reflector in conjunction with a translation stage group and an imaging system, so that the error additionally introduced due to the excessively high laser power is only related to the thermal deformation and displacement of the reflector; at the same time, the reflector is imaged, and the deformation and displacement are determined using an image algorithm, so that the error can be accurately estimated and compensated, thereby achieving accurate and reliable measurement of the diameter of the high-power laser. There is no need to perform attenuation, beam shrinkage and other transformation processing on the high-power laser, and it can accurately reflect the spatial distribution of the high-power laser along the orthogonal axis, and can flexibly select the measurement position, which is suitable for various types of high-power laser measurement needs.

[0064] It will be appreciated by those skilled in the art that the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations or combinations are not explicitly described in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0065] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A high-power laser diameter measuring device, characterized in that: include: A first reflector (1), a second reflector (2), a first bracket (3), a connecting plate (4), a first telecentric lens (5), a second telecentric lens (5'), a first image sensor (6), a second image sensor (6'), a second bracket (7), a first translation stage (8), a second translation stage (9), a detector (11), a first collector (12) and a second collector (13), wherein: The first reflector (1) and the second reflector (2) are respectively arranged on an optical path of a high-power laser beam (14) to be measured incident on a detector (11); a portion of the laser beam (14) blocked by the first reflector (1) is reflected by the first reflector (1) to a first collector (12); and a portion of the laser beam (14) blocked by the second reflector (2) is reflected by the second reflector (2) to a second collector (13); The angle between the normal line of the reflection surface of the first reflector (1) and the normal line of the reflection surface of the second reflector (2) is 60°, the movement axis of the first reflector (1), the movement axis of the second reflector (2) and the main axis of the laser beam (14) are orthogonal to each other, and the movement axis of the first reflector (1) and the normal line of the reflection surface of the first reflector (1) form an angle of 45°, and the movement axis of the second reflector (2) and the normal line of the reflection surface of the second reflector (2) form an angle of 45°; The first reflector (1) and the second reflector (2) are both mounted on a first bracket (3), and the first bracket (3) is integrally mounted on a displacement stage group consisting of a first displacement stage (8) and a second displacement stage (9) via a connecting plate (4); The first telecentric lens (5), the first image sensor (6), the second telecentric lens (5') and the second image sensor (6') are all mounted on the second bracket (7) and are respectively used to observe the first reflector (1) and the second reflector (2) in real time and to correct the positions of the first reflector (1) and the second reflector (2) through feedback from an edge detection algorithm.

2. The high-power laser diameter measuring device according to claim 1, characterized in that: The first reflector (1) and the second reflector (2) are respectively driven by the displacement stage group and scanned along orthogonal axes, thereby achieving scanning measurement of a certain cross section of the laser beam (14) by gradually blocking the beam.

3. The high-power laser diameter measuring device according to claim 2, characterized in that: The first displacement stage (8) and the second displacement stage (9) are combined with each other to form a displacement stage group having an orthogonal two-axis (x, y) scanning displacement function. When the first reflector (1) and the second reflector (2) are scanning along the orthogonal x-axis and y-axis, they move from completely not blocking the laser beam (14) to completely blocking the laser beam (14), thereby completing the scanning measurement of a certain cross section of the laser beam (14) along the x or y direction.

4. The high-power laser diameter measuring device according to claim 3, characterized in that: The device further comprises a third displacement stage (10) arranged in the z-axis direction orthogonal to both the x-axis and the y-axis. The third displacement stage (10) is combined with the first displacement stage (8) and the second displacement stage (9) to form a displacement stage group having an orthogonal three-axis (x, y, z) scanning displacement function. When scanning along the orthogonal x-axis, y-axis and z-axis, the first reflector (1) and the second reflector (2) move from completely not blocking the laser beam (14) to completely blocking the laser beam (14), thereby completing scanning measurement of a certain cross section of the laser beam (14) along the x-axis, y-axis or z-axis.

5. The high-power laser diameter measuring device according to claim 1, characterized in that: The reflective surfaces of the first reflector (1) and the second reflector (2), as well as the edges that cut into the laser beam (14), all have a high reflectivity of 95% to 99.999%, thereby reducing the amount of heat received by the reflectors.

6. The high-power laser diameter measuring device according to claim 5, characterized in that: The reflective surfaces of the first reflector (1) and the second reflector (2), as well as the edges that cut into the laser beam (14), are polished and coated.

7. The high-power laser diameter measuring device according to claim 1, characterized in that: The first reflector (1) and the second reflector (2) have a liquid cooling structure inside, or the first reflector (1) and the second reflector (2) are simultaneously cooled by high-pressure air facing the reflecting surface.

8. The high-power laser diameter measuring device according to claim 7, characterized in that: The liquid cooling structure comprises fins (21), a liquid cooling passage (22) and a sealing structure (23).

9. The high-power laser diameter measuring device according to claim 1, characterized in that: The first telecentric lens (5) and the second telecentric lens (5') are both low-distortion telecentric lenses.

10. The high-power laser diameter measuring device according to claim 9, characterized in that: The main optical axes of the first telecentric lens (5) and the first image sensor (6) are perpendicular to the reflective surface of the first reflector (1); the first image sensor (6) itself or after adding a filter has no response to the wavelength of the laser beam (14), thereby preventing the scattered light of the strong laser from damaging the first image sensor (6); The main optical axes of the second telecentric lens (5') and the second image sensor (6') are perpendicular to the reflection surface of the second reflector (2); the second image sensor (6') itself or after adding a filter has no response to the wavelength of the laser beam (14), thereby preventing the scattered light of the strong laser from damaging the second image sensor (6').

11. The high-power laser diameter measuring device according to claim 1, characterized in that: The first collector (12) is used to collect and terminate the laser light reflected by the first reflector (1) to prevent it from being reflected, refracted or scattered to other uncontrollable areas, thereby causing damage to personnel, instruments and equipment; The second collector (13) is used to collect and terminate the laser light reflected by the second reflector (2) to prevent it from being reflected, refracted or scattered to other uncontrollable areas, thereby causing damage to personnel, instruments and equipment; The first collector (12) and the second collector (13) both have a liquid cooling structure and are resistant to high-power laser damage.

12. The high-power laser diameter measuring device according to claim 1, characterized in that: The device also includes a protective cover which is arranged outside the high-power laser diameter measuring device.

Images