CN113465884B

CN113465884B - Continuous laser damage threshold testing device

Info

Publication number: CN113465884B
Application number: CN202110621727.1A
Authority: CN
Inventors: 程旺; 郭广妍; 麻云凤; 白芳; 赵鹏; 宫学程; 廖丽芬; 张思楠; 殷晨轩; 林蔚然; 樊仲维
Original assignee: Aerospace Information Research Institute of CAS
Current assignee: Aerospace Information Research Institute of CAS
Priority date: 2021-06-03
Filing date: 2021-06-03
Publication date: 2023-06-06
Anticipated expiration: 2041-06-03
Also published as: CN113465884A

Abstract

The invention provides a continuous laser damage threshold testing device which comprises a laser, an optical fiber, a QBH joint, a beam expander, a polarization beam splitter, a first analyzer, a second analyzer, a third reflector, a fourth reflector, a fifth reflector, a sixth reflector, a seventh reflector, an eighth reflector, a ninth reflector, a tenth reflector, an eleventh reflector, a polarization beam combiner, a first half-wave plate, a second half-wave plate, a first sampling mirror, a first beam splitter, a second focusing lens, a second beam splitter, an optical path compensation unit, a window mirror, a sample to be tested, a light source, a photoelectric detector, an imaging microscope, a thermal imaging detector, a second sampling mirror, a knife edge instrument and a second power meter. The invention realizes high-precision adjustment of the test power, improves the precision of the beam combination effect and realizes high-precision adjustment of the pointing direction of the test light spot.

Description

Continuous laser damage threshold testing device

Technical Field

The invention relates to the technical field of semiconductor lasers, in particular to a continuous laser damage threshold testing device.

Background

With the gradual expansion of the application range of the high-power laser in optical fiber laser pumping or industrial processing, the performance requirements of people on the high-power laser are also higher and higher. The high-power laser is divided into pulse laser and continuous laser, wherein the high-power continuous laser is widely applied to the fields of laser processing, cladding, welding and the like. The laser damage threshold of optical elements used in high power continuous lasers has largely limited the further use of lasers.

In the process of implementing the disclosed concept, the inventor finds that at least the following problems exist in the related art: the existing continuous laser testing device has the defects of limited adjusting precision, low integration degree, single testable sample and poor measuring environment adjustability.

Disclosure of Invention

In order to improve the damage threshold judgment precision of a continuous laser, the invention provides a continuous laser damage threshold testing device.

The invention provides a continuous laser damage threshold testing device, which comprises a laser LS, an optical fiber RA, a QBH joint, a beam expander EX, a polarization beam splitter PB, a first analyzer P1, a second analyzer P2, a third reflector RM3, a fourth reflector RM4, a fifth reflector RM5, a sixth reflector RM6, a seventh reflector RM7, an eighth reflector RM8, a ninth reflector RM9, a tenth reflector RM10, an eleventh reflector RM11, a polarization beam combiner BC, a first half-wave plate HW1, a second half-wave plate HW2, a first sampling mirror SP1, a first beam splitter BS1, a second focusing lens FC2, a second beam splitter BS2, an optical path compensation unit OP, a window mirror WD, a sample SA to be tested, a light source LG, a photoelectric detector PL, an imaging microscope IM, a thermal imaging detector TM, a second sampling mirror SP2, a knife edge ED and a second power meter PW2, wherein:

laser emitted by the laser LS is collimated by the optical fiber RA and the QBH joint in sequence and then is led into the beam expander EX to obtain beam-expanded laser, and the beam-expanded laser is split into a transmission beam and a reflection beam by the polarization beam splitter PB;

the transmitted light beam is guided to a polarization beam combining lens BC after being reflected and deflected by the light paths of a second analyzer P2, a third reflector RM3 and a fourth reflector RM4 in sequence, and the reflected light beam is guided to the polarization beam combining lens BC after being reflected and deflected by the light paths of a fifth reflector RM5, a sixth reflector RM6 and a seventh reflector RM7 in sequence;

the first half wave plate HW1 and the second half wave plate HW2 are respectively used for regulating the polarization states of the reflected light beam and the transmitted light beam, and respectively cooperate with the first analyzer P1 and the second analyzer P2 to realize high-precision regulation of the mutually perpendicular polarization state laser power, and the polarization beam combiner BC is used for combining the mutually perpendicular polarization state laser and outputting combined laser;

the first sampling mirror SP1 is disposed on the outgoing optical path of the polarization beam combining mirror BC, and is configured to split the combined laser beam into a first reflected sub-beam and a first transmitted sub-beam, where the first transmitted sub-beam sequentially passes through the transmission of the first beam splitter BS1, the reflection of the eighth mirror RM8, the ninth mirror RM9, and the tenth mirror RM10 to obtain a second reflected sub-beam, and the second reflected sub-beam sequentially passes through the second focusing lens FC2 and the second beam splitter BS2 and is split again into a third reflected sub-beam and a third transmitted sub-beam;

the third transmission sub-beam sequentially passes through an optical path compensation unit OP and a window mirror WD and then is converged on the surface of the sample SA to be measured, and the optical path compensation unit OP is used for compensating optical path differences generated when the laser irradiates different positions of the sample;

a light source LG, a photoelectric detector PL, an imaging microscope IM and a thermal imaging detector TM are arranged around the sample SA to be measured;

the third reflected sub-beam is sequentially reflected by the eleventh reflecting mirror RM11 and transmitted by the second sampling mirror SP2, and then is connected to the second power meter PW2 via the knife edge instrument ED, where the knife edge instrument ED cooperates with the second power meter PW2 to measure the beam width or beam diameter.

In some embodiments, the laser LS is a randomly polarized continuous laser light source and the optical fiber RA is a dispersion compensating fiber.

In some embodiments, the first half wave plate HW1 is disposed between the polarizing beam splitter PB and the fifth mirror RM5 for converting the reflected light beam into P polarized light; the second half wave plate HW2 is disposed between the polarization beam splitter PB and the second analyzer P2, and is configured to convert the transmitted beam into S polarized light.

In some embodiments, further comprising a first mirror RM1, a second mirror RM2, and an optical trap LT, wherein: the light beam transmitted through the second analyzer P2 is sequentially introduced into the optical trap LT via the first mirror RM1 and the second mirror RM2, and the light beam reflected through the first analyzer P1 is also introduced into the optical trap LT for absorbing stray light due to low linearity of the transmitted light beam and the reflected light beam.

In some embodiments, further comprising a first focusing lens FC1, a first attenuation sheet AT1, and a first detector PD1, wherein: the first reflected sub-beam sequentially passes through the first focusing lens FC1 and the first attenuation sheet AT1 and is introduced into the first detector PD1, and the first detector PD1 is used for detecting the far-field spot overlap ratio of the reflected sub-beam; the first detector PD1 is disposed at the imaging focal position of the focusing lens FC.

In some embodiments, further comprising a first power meter PW1, wherein: the first transmitted sub-beam is reflected by the first beam splitter BS1 and then is connected to the first power meter PW1, where the first power meter PW1 is used to measure the laser power reflected by the first beam splitter BS 1.

In some embodiments, all mirrors are 45 ° total reflection mirrors, wherein the third mirror RM3, the fourth mirror RM4, the fifth mirror RM5, and the sixth mirror RM6 are mounted on an adjustable mirror mount for adjusting the beam direction.

In some embodiments, the first detector PD1 is a CCD charge coupled device or a PSD photo-detector.

In some embodiments, the optical axes of the polarization beam combiner BC, the first sampling mirror SP1, and the first beam splitter BS1 are coaxial, and the optical axes of the second beam splitter BS2, the optical path compensation unit OP, and the window mirror WD are coaxial.

In some embodiments, the optical path compensation unit OP is a double wedge mirror.

In some embodiments, the edge detector ED is disposed on an electric displacement stage, and the electric displacement stage is configured to control the edge detector ED to be disposed on an optical axis of an incident beam of the second power meter PW2, and control the edge detector ED to move along a direction perpendicular to the incident beam of the second power meter PW2, so that the detection power of the second power meter PW2 is gradually reduced.

In some embodiments, further comprising: a twelfth mirror RM12, a second attenuator AT2, and a second detector PD2, wherein: the third reflected sub-beam is sequentially reflected by the light paths of the eleventh reflecting mirror RM11, the second sampling mirror SP2 and the twelfth reflecting mirror RM12, and then is introduced into the second detector PD2 through the second attenuation sheet AT2, the distances between the second detector PD2 and the sample to be measured SA and the second focusing lens FC2 are the same, and the second detector PD2 is used for detecting the focused spot size of the third reflected sub-beam.

In some embodiments, further comprising a far field pointing control unit FP, wherein: the light beam transmitted by the tenth reflecting mirror RM10 is led to the far-field pointing control unit FP, where the far-field pointing control unit FP is configured to detect the far-field spot position information of the transmitted light beam, so as to control and adjust the optical axis overlap ratio of the seventh reflecting mirror RM7 and the eighth reflecting mirror RM8, and realize high-precision light beam pointing control.

In some embodiments, the far field pointing control unit FP comprises near field and far field spot position sensitive detectors of the light beam.

In some embodiments, the laser light emitted from the light source LG is reflected by the surface of the sample to be measured SA to the photodetector PL, which is used to detect the scattered signal passing through the sample to be measured SA, the imaging microscope IM is used to detect the reflectance change of the surface of the sample to be measured SA, and the thermal imaging detector TM is used to detect the plasma and thermal radiation of the sample to be measured SA due to the excitation of the laser light.

Compared with the prior art, the invention has at least the following beneficial effects:

(1) The invention provides a damage threshold measuring device with high precision, high integration and multiple judging methods, which realizes high-precision adjustment of test power, improves the precision of beam combination effect and high-precision adjustment of the pointing direction of a test light spot;

(2) The invention provides a high-precision adjusting system for designing laser power for test, which is characterized in that an adjustable unit is designed to improve the environmental adaptability of the system, and a monitoring unit is designed to ensure the light path output effect;

(3) The measuring device provided by the invention can be suitable for lasers and measuring equipment with different parameters, and can be applied to a multi-beam combination system;

(4) The near-field and far-field monitoring module can be developed into a special product for realizing high-precision laser beam combination.

Drawings

FIG. 1 shows a schematic structural diagram of a continuous laser damage threshold testing device according to an embodiment of the present invention;

fig. 2 shows a schematic diagram of an optical path length compensation unit according to an embodiment of the present invention.

[ reference numerals description 1 ]

LS-laser; RA-fiber; EX-beam expander; PB-polarization beam splitter;

HW 1-first half-wave plate; HW 2-second half-wave plate;

p1-a first analyzer; p2-a second analyzer; LT-optical trap;

RM 1-a first mirror; RM 2-second mirror; RM 3-third mirror;

RM 4-fourth mirror; RM 5-fifth mirror; RM 6-sixth mirror;

RM 7-seventh mirror; RM 8-eighth mirror; RM 9-ninth mirror;

RM 10-tenth mirror; RM 11-eleventh mirror; RM 12-twelfth mirror;

BC-polarization beam combiner; SP 1-a first sampling mirror; SP 2-a second sampling mirror;

FC 1-a first focusing lens; FC 2-second focusing lens;

BS 1-first beam splitter; BS 2-second beam splitter;

FP-far field pointing control unit; ED-knife edge instrument;

an OP-optical path compensation unit; WD-window mirror; SA-sample to be measured;

LG-light source; PL-photodetectors; IM-imaging microscope; TM-thermal imaging detector;

PW 1-a first power meter; PW 2-a second power meter;

AT 1-a first attenuation sheet; AT 2-a second attenuation sheet;

PD 1-a first detector; PD 2-second detector.

Detailed Description

The present invention will be further described in detail below with reference to specific embodiments and with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and/or the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.

Before describing the continuous laser damage threshold testing device of the invention in detail, two testing modes of the laser damage threshold, namely an R-on-1 mode and a 1-on-1 mode, are briefly described.

R-on-1 injury test mode-for the same spot on the sample being tested, the sample is repeatedly irradiated with increasing laser energy until injury occurs. The initial laser energy is required to be far smaller than the damage threshold of the sample during the test, and the pulse laser energy causing the damage of the sample is recorded, namely the damage threshold of the point is considered. And then measuring damage threshold values of a plurality of points on the same sample, and obtaining an average value to obtain the damage threshold value of the measured sample.

1-on-1 injury test mode-also known as zero-probability injury method. The number n of lesions was recorded using a single pulse laser of the same energy to irradiate m spots. Each energy laser irradiation damage probability P is equal to n/m. The laser energy was varied and the probability of damage at the varied laser energy was measured, including energy points with a probability of damage of 0 and 100%. And (3) taking laser energy as a horizontal axis and the damage probability as a vertical axis, obtaining the distribution of the damage probability and the laser energy points, and then linearly fitting and extrapolating to zero damage probability, wherein the corresponding laser energy value is the damage threshold value of the tested sample.

The invention aims to improve the damage threshold value judgment precision of a high-power continuous laser, and provides a damage threshold value measuring device with high precision, high integration and multiple judgment method coupling.

Embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

Fig. 1 shows a schematic structural diagram of a continuous laser damage threshold testing device according to an embodiment of the present invention.

As shown in fig. 1, the continuous laser damage threshold testing apparatus may include: laser LS, optical fiber RA, QBH joint, beam expander EX, polarization beam splitter PB, first analyzer P1, second analyzer P2, third mirror RM3, fourth mirror RM4, fifth mirror RM5, sixth mirror RM6, seventh mirror RM7, eighth mirror RM8, ninth mirror RM9, tenth mirror RM10, eleventh mirror RM11, polarization beam combiner BC, first half-wave plate HW1, second half-wave plate HW2, first sampling mirror SP1, first beam splitter BS1, second focusing lens FC2, second beam splitter BS2, optical path compensation unit OP, window mirror, sample under test SA, light source LG, photodetector PL, imaging microscope IM, thermal imaging detector TM, second sampling mirror SP2, knife edge meter ED and second power meter PW2.

The laser emitted by the laser LS is collimated by the optical fiber RA and the QBH joint in sequence and then is led into the beam expander EX to obtain beam-expanded laser, and the beam-expanded laser is split into a transmission beam and a reflection beam by the polarization beam splitter PB;

In the embodiment of the invention, the laser LS is a random polarization continuous laser source, and the optical fiber RA is a dispersion compensation optical fiber.

The first half wave plate HW1 is disposed between the polarization beam splitter PB and the fifth mirror RM5, and is used for converting the reflected light beam into P polarized light; the second half wave plate HW2 is disposed between the polarization beam splitter PB and the second analyzer P2, and is configured to convert the transmitted beam into S polarized light.

It will be appreciated that a beam of light is subjected to a half wave plate with the vibration direction reversed by 90 deg., and that a half wave plate may be used to change the polarization state of the beam of light. Since the polarization directions of the P-polarized light and the S-polarized light are perpendicular to each other, that is, the two form a laser light of a mutually perpendicular polarization state.

Further, the second analyzer P2 is configured to detect a polarization state of the laser after the transmitted beam is converted; the first analyzer P1 is disposed between the first half-wave plate HW1 and the fifth mirror RM5, and is configured to detect the polarization state of the converted laser beam.

Therefore, after the laser output by the laser LS is collimated and expanded, the laser is split into two linearly polarized lights P and S by the polarization beam splitter PB. The laser collimation ensures that the light spot size is unchanged within the transmission distance; the laser beam expansion is to ensure that the power density is still within the range of the damage threshold of the transmission element under the condition of high power output of the laser. The combination of the half-wave plate and the polarizer is to make adjustments of the laser power in both polarization states.

According to the embodiment of the invention, the light paths before the transmitted light beam and the reflected light beam pass through the polarization beam combining lens BC are independent of each other, the polarization beam combining lens BC is provided with two light incident surfaces and one light emergent surface, the two light incident surfaces are respectively used for receiving mutually perpendicular polarized laser formed by converting the linear polarized laser emitted by the transmitted light beam and the reflected light beam, the mutually perpendicular polarized laser carries out polarization beam combining through the polarization beam combining lens BC to form one path of light beam to emit, and the one path of light beam is the combined laser.

Continuing with fig. 1, the continuous laser damage threshold testing device further comprises a first mirror RM1, a second mirror RM2, and an optical trap LT, wherein: the light beam transmitted through the second analyzer P2 is sequentially introduced into the optical trap LT via the first mirror RM1 and the second mirror RM2, and the light beam reflected through the first analyzer P1 is also introduced into the optical trap LT for absorbing stray light due to low linearity of the transmitted light beam and the reflected light beam. Thus, the light beams not utilized by the transmitted light beam and the reflected light beam are uniformly absorbed to the optical trap LT.

The continuous laser damage threshold testing device further comprises a first power meter PW1, wherein: the first transmitted sub-beam is reflected by the first beam splitter BS1 and then is connected to the first power meter PW1, where the first power meter PW1 is used to measure the laser power reflected by the first beam splitter BS1, so as to monitor the stability of the laser power.

In order to improve the beam quality of the testing device, in the embodiment of the present invention, the optical axes of the polarization beam combiner BC, the first sampling mirror SP1 and the first beam splitter BS1 are coaxial, and the optical axes of the second beam splitter BS2, the optical path compensation unit OP and the window mirror WD are coaxial.

In the embodiment of the invention, all the reflectors are 45-degree total reflectors, wherein a third reflector RM3, a fourth reflector RM4, a fifth reflector RM5 and a sixth reflector RM6 are mounted on an adjustable mirror bracket, and the adjustable mirror bracket is used for adjusting the beam direction.

In order to realize high-precision real-time adjustment, the adjustable mirror bracket can adopt a manual or electric control mode.

The first detector PD1 and the second detector PD2 are both CCD charge coupled devices or PSD photo-electric position sensitive detectors.

It can be understood that the Charge Coupled Device (CCD) measures the far-field light spot of the laser by a light spot imaging method, and the method has the advantages of non-contact measurement, simple structure, convenient operation and higher spatial resolution. The photoelectric sensitive detector (position sensitive detector, PSD) is an ultra-fast response speed and ultra-high resolution LED optical displacement measuring device, and can remotely measure the two-dimensional dynamic displacement of a target.

Since the CCD is extremely vulnerable to laser, and if the light is too strong, the gray level supersaturation of the light spot on the gray level map formed on the CCD can be caused, and the positioning of the center of the light spot is affected. Thus, the reflected and transmitted beamlets that pass through the sampling mirror need to be attenuated as necessary to enter the detector, which would otherwise cause damage to the CCD camera.

As further shown in fig. 1, the continuous laser damage threshold testing device further includes a first focusing lens FC1, a first attenuation sheet AT1, and a first detector PD1, wherein: the first reflected sub-beam sequentially passes through the first focusing lens FC1 and the first attenuation sheet AT1 to be introduced into the first detector PD1, and the first detector PD1 is used for detecting the far-field spot overlap ratio of the reflected sub-beam.

Preferably, the first detector PD1 is disposed at the imaging focal position of the focusing lens FC. Because the reflected sub-beam passing through the sampling mirror is usually low-power laser, the sampling mirror of the embodiment is used for real-time monitoring of the far-field spot overlap ratio of the two light sources by reflecting the low-power laser.

The continuous laser damage threshold testing device further comprises: a twelfth mirror RM12, a second attenuator AT2, and a second detector PD2, wherein: the third reflected sub-beam is sequentially reflected by the light paths of the eleventh reflecting mirror RM11, the second sampling mirror SP2 and the twelfth reflecting mirror RM12, and then is introduced into the second detector PD2 through the second attenuation sheet AT2, the distances between the second detector PD2 and the sample to be measured SA and the second focusing lens FC2 are the same, and the second detector PD2 is used for detecting the focused spot size of the third reflected sub-beam.

As shown in fig. 2, in the embodiment of the present invention, the optical path compensation unit OP is a double wedge mirror.

Specifically, when the damage threshold test is performed on a high-reflection sample, in order to protect the laser light source and the test system, the sample needs to be fixed at a certain angle with the laser transmission direction during installation. Because the driving direction of the sample is perpendicular to the transmission direction of the light beam, optical path difference is generated when the laser irradiates different positions of the sample, so that the diameters of the light beams of different test points are different, and the test precision is affected. Based on the principle that the transmission optical path of laser in different media is different, the optical path difference is compensated in real time by utilizing the double wedge-shaped mirrors.

Based on the above optical path compensation principle, as shown in fig. 2, the optical path difference compensation of the double wedge mirror should satisfy the following relationship:

nΔy＝Δx

Δx＝lsinθ

wherein, the wedge stepping should satisfy the following relationship:

the sample step should satisfy the following relationship:

wherein: alpha-top angle of wedge; θ—the angle between the sample and the vertical axis plane; n-the refractive index of the optical wedge medium; Δy—single wedge step optical path difference; Δx—sample step path difference; l-the distance between two points of the laser irradiation sample; ΔH-the step distance of the sample along the vertical axis; Δh—the step distance of the wedge plate along the vertical axis.

By the embodiment of the invention, the optical path difference generated when the laser irradiates different positions of the sample can be compensated in real time by using the double wedge-shaped mirrors.

In the embodiment of the invention, the knife edge instrument ED is arranged on an electric displacement table, and the electric displacement table is used for controlling the knife edge instrument ED to be arranged on the optical axis of the incident light beam of the second power meter PW2 and controlling the knife edge instrument ED to move along the direction perpendicular to the incident light beam of the second power meter PW2 so as to gradually reduce the detection power of the second power meter PW2.

The continuous laser damage threshold testing device further comprises a far-field pointing control unit FP, wherein: the light beam transmitted by the tenth reflecting mirror RM10 is led to the far-field pointing control unit FP, where the far-field pointing control unit FP is configured to detect the far-field spot position information of the transmitted light beam, so as to control and adjust the optical axis overlap ratio of the seventh reflecting mirror RM7 and the eighth reflecting mirror RM8, and realize high-precision light beam pointing control.

Specifically, far field pointing control unit FP includes near field and far field spot Position Sensitive Detectors (PSDs) of the light beam. Therefore, the far-field pointing control unit FP can adjust the seventh mirror RM7 and the eighth mirror RM8 according to the position information of the light spot, so as to realize high-precision light spot far-field pointing control.

The outgoing laser of the light source LG is reflected to a photoelectric detector PL through the surface of the sample SA to be detected, the photoelectric detector PL is used for detecting a scattered signal passing through the sample SA to be detected, the imaging microscope IM is used for detecting the reflectivity change of the surface of the sample SA to be detected, and the thermal imaging detector TM is used for detecting plasma and thermal radiation of the sample SA to be detected due to laser excitation.

Therefore, the testing device provided by the embodiment of the invention integrates a scattering detection method, an online microscopy method, a transmittance change online detection method and a plasma detection method.

Furthermore, the testing device provided by the invention can be suitable for lasers and measuring equipment with different parameters, and can be applied to a multi-beam combination system. In addition, the near-field and far-field light spot coincidence degree detector can be developed into a special product and used for realizing high-precision laser beam combination.

In summary, the invention provides a continuous laser damage threshold testing device, and provides a high-precision adjusting system for designing laser power for testing, which designs an adjustable unit to improve the environmental adaptability of the system, designs a monitoring unit to ensure the output effect of an optical path, and realizes high-precision adjustment of the testing power, improvement of the precision of the beam combining effect and high-precision adjustment of the pointing direction of a testing light spot.

It should be further noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "rear", "left", "right", etc., are only with reference to the directions of the drawings, and are not intended to limit the scope of the present disclosure. Like elements are denoted by like or similar reference numerals throughout the drawings. Conventional structures or constructions will be omitted when they may obscure the understanding of this disclosure. And the shape, size and position relation of each component in the figure do not reflect the actual size, proportion and actual position relation.

Similarly, in the foregoing description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various disclosed aspects. The description of the reference to the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

While the foregoing is directed to embodiments of the present invention, other and further details of the invention may be had by the present invention, it should be understood that the foregoing description is merely illustrative of the present invention and that no limitations are intended to the scope of the invention, except insofar as modifications, equivalents, improvements or modifications are within the spirit and principles of the invention.

Claims

1. The device is characterized by comprising a Laser (LS), an optical fiber (RA), a QBH joint, a beam Expander (EX), a polarization beam splitter (PB), a first analyzer (P1), a second analyzer (P2), a third reflector (RM 3), a fourth reflector (RM 4), a fifth reflector (RM 5), a sixth reflector (RM 6), a seventh reflector (RM 7), an eighth reflector (RM 8), a ninth reflector (RM 9), a tenth reflector (RM 10), an eleventh reflector (RM 11), a polarization Beam Combiner (BC), a first half-wave plate (HW 1), a second half-wave plate (HW 2), a first sampling mirror (SP 1), a first beam splitter (BS 1), a second focusing lens (FC 2), a second beam splitter (BS 2), an optical path compensation unit (OP), a window mirror (WD), a sample to be tested (LG), a light source (PL), an Imaging Microscope (IM), a thermal imaging detector (TM), a second sampling mirror (SP 2), a PW 2) and a second power meter (SA 2), wherein:

laser emitted by a Laser (LS) is collimated by an optical fiber (RA) and a QBH joint and then is led into a beam Expander (EX) to obtain beam-expanded laser, and the beam-expanded laser is split into a transmission beam and a reflection beam by a polarization beam splitter (PB);

the transmitted light beam is guided to a polarization beam combining mirror (BC) after being reflected and deflected by a light path of a second half wave plate (HW 2), a second analyzer (P2), a third reflector (RM 3) and a fourth reflector (RM 4) in sequence, and the reflected light beam is guided to the polarization beam combining mirror (BC) after being reflected and deflected by a light path of a first half wave plate (HW 1), the first analyzer (P1), a fifth reflector (RM 5), a sixth reflector (RM 6) and a seventh reflector (RM 7) in sequence;

the first half wave plate (HW 1) and the second half wave plate (HW 2) are respectively used for regulating the polarization states of the reflected light beam and the transmitted light beam, and are respectively matched with the first analyzer (P1) and the second analyzer (P2) to realize high-precision regulation of the mutually perpendicular polarization state laser power, and the polarization Beam Combiner (BC) is used for combining the mutually perpendicular polarization state laser and outputting combined laser;

the first sampling mirror (SP 1) is arranged on an emergent light path of the polarization beam combining mirror (BC) and is used for dividing the combined laser beam into a first reflected sub-beam and a first transmitted sub-beam, the first transmitted sub-beam sequentially passes through transmission of the first beam splitter (BS 1), reflection of the eighth reflecting mirror (RM 8), reflection of the ninth reflecting mirror (RM 9) and reflection of the tenth reflecting mirror (RM 10) to obtain a second reflected sub-beam, and the second reflected sub-beam sequentially passes through the second focusing lens (FC 2) and the second beam splitter (BS 2) and is divided into a third reflected sub-beam and a third transmitted sub-beam again;

the third transmission sub-beam sequentially passes through an optical path compensation unit (OP) and a window mirror (WD) and then is converged on the surface of the Sample (SA) to be measured, and the optical path compensation unit (OP) is used for compensating optical path differences generated when the sample is irradiated by laser at different positions;

a light source (LG), a photoelectric detector (PL), an Imaging Microscope (IM) and a thermal imaging detector (TM) are arranged around the Sample (SA) to be detected;

the third reflected sub-beam is connected to a second power meter (PW 2) through a knife edge instrument (ED) after being sequentially reflected by an eleventh reflecting mirror (RM 11) and transmitted by a second sampling mirror (SP 2), and the knife edge instrument (ED) is matched with the second power meter (PW 2) to realize measurement of the beam width or the beam diameter.

2. The continuous laser damage threshold testing device according to claim 1, wherein the Laser (LS) is a randomly polarized continuous laser light source and the optical fiber (RA) is a dispersion compensating fiber.

3. The continuous laser damage threshold testing device according to claim 1, characterized in that the first half wave plate (HW 1) is used for converting the reflected light beam into P-polarized light;

the second half wave plate (HW 2) is arranged for converting the transmitted light beam into S polarized light.

4. The continuous laser damage threshold testing device according to claim 1, further comprising a first mirror (RM 1), a second mirror (RM 2) and an optical trap (LT), wherein:

the light beam transmitted through the second analyzer (P2) is sequentially introduced into an optical trap (LT) through a first reflector (RM 1) and a second reflector (RM 2), and the light beam reflected through the first analyzer (P1) is also introduced into the optical trap (LT), wherein the optical trap (LT) is used for absorbing stray light caused by low linearity of the transmitted light beam and the reflected light beam.

5. The continuous laser damage threshold testing device of claim 1, further comprising a first focusing lens (FC 1), a first attenuation sheet (AT 1), and a first detector (PD 1), wherein:

the first reflected sub-beam sequentially passes through a first focusing lens (FC 1) and a first attenuation sheet (AT 1) and is introduced into a first detector (PD 1), and the first detector (PD 1) is used for detecting the far-field spot overlap ratio of the reflected sub-beam;

the first detector (PD 1) is disposed at an imaging focal position of the focusing lens (FC).

6. The continuous laser damage threshold testing device of claim 1, further comprising a first power meter (PW 1), wherein:

the first transmission sub-beam is connected to a first power meter (PW 1) after being reflected by a first beam splitter (BS 1), and the first power meter (PW 1) is used for measuring laser power after being reflected by the first beam splitter (BS 1).

7. The continuous laser damage threshold testing device according to claim 1, wherein all mirrors are 45 ° total reflection mirrors, wherein the third mirror (RM 3), the fourth mirror (RM 4), the fifth mirror (RM 5) and the sixth mirror (RM 6) are mounted on an adjustable mirror mount for adjusting the beam direction.

8. The continuous laser damage threshold testing device according to claim 5, wherein the first detector (PD 1) is a CCD charge coupled device or a PSD photo-detector.

9. The continuous laser damage threshold testing device according to claim 1, wherein the optical axes of the polarization Beam Combiner (BC), the first sampling mirror (SP 1) and the first beam splitter (BS 1) are coaxial, and the optical axes of the second beam splitter (BS 2), the optical path compensation unit (OP) and the window mirror (WD) are coaxial.

10. The continuous laser damage threshold testing device according to claim 1, wherein the optical path compensation unit (OP) is a double wedge mirror.

11. The continuous laser damage threshold testing device according to claim 1, wherein the Edge Detector (ED) is disposed on an electric displacement stage, and the electric displacement stage is configured to control the Edge Detector (ED) to be disposed on an optical axis of an incident beam of the second power meter (PW 2), and control the Edge Detector (ED) to move in a direction perpendicular to the incident beam of the second power meter (PW 2), so that the detection power of the second power meter (PW 2) is gradually reduced.

12. The continuous laser damage threshold testing device of claim 1, further comprising: a twelfth mirror (RM 12), a second attenuation sheet (AT 2), and a second detector (PD 2), wherein:

the third reflected sub-beam is sequentially reflected by the light paths of the eleventh reflecting mirror (RM 11), the second sampling mirror (SP 2) and the twelfth reflecting mirror (RM 12) and then is led into the second detector (PD 2) through the second attenuation sheet (AT 2);

the second detector (PD 2) and the Sample (SA) to be detected are respectively the same in distance from the second focusing lens (FC 2), and the second detector (PD 2) is used for detecting the focusing spot size of the third reflection sub-beam.

13. The continuous laser damage threshold testing device according to claim 1, further comprising a far field pointing control unit (FP), wherein:

the light beam transmitted by the tenth reflecting mirror (RM 10) is led into the far-field pointing control unit (FP), and the far-field pointing control unit (FP) is used for detecting far-field spot position information of the transmitted light beam so as to control and adjust the optical axis coincidence degree of the seventh reflecting mirror (RM 7) and the eighth reflecting mirror (RM 8) and realize high-precision light beam pointing control.

14. The continuous laser damage threshold testing device of claim 13, wherein the far field pointing control unit (FP) comprises near field and far field spot position sensitive detectors of the light beam.

15. The continuous laser damage threshold testing device according to claim 1, wherein the emitted laser light of the light source (LG) is reflected by the surface of the Sample (SA) to be tested to a Photodetector (PL) for detecting scattered signals passing through the Sample (SA) to be tested, the Imaging Microscope (IM) is used for detecting reflectivity changes of the surface of the Sample (SA) to be tested, and the thermal imaging detector (TM) is used for detecting plasma and thermal radiation of the Sample (SA) to be tested due to laser excitation.