Disclosure of Invention
The invention aims to provide a laser system which can be applied to the damage characteristic test of an optical element, can adjust the spot size of output laser and is beneficial to improving the test efficiency and the test accuracy. The invention also provides a laser-induced damage testing system and method.
In order to achieve the purpose, the invention provides the following technical scheme:
a laser system comprises a laser generating device, a beam control device and a converging device, wherein the laser generating device is used for generating laser beams and enabling the laser beams to be incident to the beam control device, the beam control device is used for shaping the laser beams to control the size of a light spot formed by output laser, and the converging device is used for converging the laser beams emitted by the beam control device and emitting the laser beams.
Preferably, the beam control device comprises a convex lens and a concave lens, and the beam control device is specifically used for shaping the laser beam by changing the distance between two adjacent lenses or the distance between a lens and the converging device.
Preferably, the laser device further comprises an energy control device for regulating and controlling the energy of the laser beam.
Preferably, the laser device further comprises a first light splitting device and a beam quality monitoring device, the first light splitting device is used for splitting the laser beam emitted by the converging device into sub-beams, and the beam quality monitoring device is used for acquiring the energy distribution of the sub-beams.
Preferably, the laser device further comprises a second light splitting device and an energy measuring device, the second light splitting device is used for splitting the laser beam emitted by the converging device into the sub-beams, and the energy measuring device is used for measuring the energy of the sub-beams.
Preferably, the energy distribution data of the laser beam is obtained according to the following formula:
Where M denotes a relative energy distribution of the measured laser beam, E denotes a total energy of the measured laser beam, and M' denotes actual energy distribution data of the obtained laser beam.
A laser-induced damage test system comprises a laser system for projecting laser to the surface of a test element, wherein the laser system is adopted.
A laser induced damage testing method using the laser system described above, the method comprising:
when the laser generating device outputs laser, acquiring surface information of a test point on a test element, and triggering and starting a first timer;
when the set time of the first timer is over, moving the next test point of the test element to the target position, and triggering to start a second timer;
and when the set time of the second timer is over, if the next test point of the test element reaches the target position, acquiring the surface information of the next test point on the test element, and triggering and starting a third timer.
Preferably, when the time set by the second timer is over, if the next test point of the test element does not reach the target position, the laser beam generated by the laser system is blocked from being projected to the next test point of the test element.
Preferably, the method comprises the following steps:
for each test point of a test area on a test element, obtaining a damage morphology image corresponding to the test point according to images of the test point before and after being irradiated by laser;
splicing the damage morphology images corresponding to the test points of the test area;
and obtaining a damage test result of the test area according to the spliced image.
According to the technical scheme, the laser system comprises a laser generating device, a beam control device and a converging device, wherein the laser generating device is used for generating laser beams and enabling the laser beams to be incident to the beam control device, the beam control device is used for shaping the laser beams to control the size of a light spot formed by output laser, and the converging device is used for converging the laser beams emitted by the beam control device and emitting the laser beams. The laser system can adjust the size of the light spot of the output laser, can be applied to the damage characteristic test of the optical element, and is beneficial to improving the test efficiency.
The laser-induced damage testing system provided by the invention can achieve the beneficial effects.
The laser-induced damage testing method provided by the invention can achieve the beneficial effects.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic diagram of a laser system provided in this embodiment, as can be seen from the figure, the laser system includes alaser generating device 100, abeam control device 101 and aconverging device 102, thelaser generating device 100 is configured to generate a laser beam and make the laser beam incident to thebeam control device 101, thebeam control device 101 is configured to shape the laser beam to control a spot size formed by output laser, and theconverging device 102 is configured to converge and emit the laser beam emitted by thebeam control device 101.
Thebeam control device 101 is used for shaping the laser beam, so that the size of a light spot formed by the laser output by the laser system can be controlled, and the size of the light spot formed by the laser output by the laser system can be adjusted. The laser system of this embodiment can adjust output laser facula size, can be applied to the damage characteristic test to optical element, can adjust output laser facula size according to the test demand, helps improving efficiency of software testing and test accuracy.
Thelaser generating apparatus 100 may employ various lasers that meet the application requirements.
Alternatively, thebeam control device 101 may employ a convex lens and a concave lens, and thebeam control device 101 is specifically configured to shape the laser beam by changing the distance between two adjacent lenses or the distance between a lens and theconverging device 102. In practical applications, the lightbeam control device 101 may comprise a plurality of convex lenses, or the lightbeam control device 101 comprises a plurality of concave lenses, or the lightbeam control device 101 comprises at least one convex lens and at least one concave lens.
Referring to fig. 2 exemplarily, fig. 2 is a schematic diagram of a laser system according to another embodiment, where abeam control device 101 used in the laser system shown in fig. 2 includes aconvex lens 103 and aconcave lens 104, and the radial size of the laser beam is adjusted by controlling a distance between theconvex lens 103 and theconcave lens 104, a distance between theconvex lens 103 and theconverging device 102, or a distance between theconcave lens 104 and theconverging device 102. Referring to fig. 3(a) and 3(b), fig. 3(a) and 3(b) are schematic layout views of the convex lens, the concave lens and the converging device in two arrangements, respectively, in which the distances between theconvex lens 103 and theconcave lens 104 are different, and the sizes of the light spots projected onto the surface of the test element by the corresponding laser systems are different.
Preferably, the laser system may further include a linear displacement stage for carrying the convex lens or the concave lens, and the convex lens or the concave lens is moved by the linear displacement stage. Referring to fig. 2, theconvex lens 103 and theconcave lens 104 are respectively disposed on thelinear displacement stage 105, and preferably, thelinear displacement stage 105 may be a high-precision electric linear displacement stage to ensure relative precision of the lens position movement.
Further referring to fig. 2, the laser system further includes a filteringoptical element 107 and afiltering aperture 108 disposed on a light path between thelaser generating device 100 and thebeam control device 101, wherein the filteringoptical element 107 is configured to converge the laser beam to thefiltering aperture 108, and thefiltering aperture 108 is configured to block high-frequency waves in the laser beam from passing through. The beam quality of the laser beam is improved by thefilter optics 107 and thefilter aperture 108.
Further preferably, the laser system further comprises an energy control device for regulating and controlling the energy of the laser beam, so that the laser system can regulate the energy of the output laser to output the laser with corresponding energy according to the test requirement on the test element, and the laser system can provide a laser energy step through the energy control device to meet the test requirement. Referring to fig. 2, theenergy control device 106 may be disposed on the optical path between thelaser generating device 100 and thebeam control device 101.
Optionally, theenergy control device 106 may include a modulation element and a beam splitting element, the modulation element is configured to decompose the laser beam into two vibration components with mutually orthogonal vibration directions, and the beam splitting element is configured to separate the two vibration components of the laser beam into two beams, so as to achieve adjustment and control of the energy of the laser beam. The modulation element may be, but is not limited to, an 1/4 wave plate, and the beam splitting element may be, but is not limited to, a polarization beam splitter prism. The energy of the emergent laser can be regulated and controlled by rotating the modulation element to change the included angle between the polarization direction of the incident laser and the optical axis of the modulation element. For example, the modulation element can be fixed on a rotary table, and the rotation angle of the modulation element can be accurately controlled through the rotary table, so that the purpose of accurately controlling energy attenuation is achieved.
Optionally, referring to fig. 2, the laser system may further include ashutter 109 for allowing or blocking the laser beam to pass through. The present laser system can control the output of laser light and control the output frequency of laser light through theshutter 109.
Preferably, the laser system of this embodiment may further include a first light splitting device and a beam quality monitoring device, where the first light splitting device is configured to split the laser beam emitted by the converging device into sub-beams, and the beam quality monitoring device is configured to obtain energy distributions of the sub-beams. Referring to fig. 2, the firstlight splitting device 110 is disposed on the light path exiting from the convergingdevice 102, and the firstlight splitting device 110 reflects part of the laser light to the detection surface of the beamquality monitoring device 111. Preferably, the position of the detection surface of the beamquality monitoring device 111 and the position of the surface of the test element are conjugated with respect to the firstlight splitting device 110 to ensure that the quality of the beam detected by the beamquality monitoring device 111 is consistent with the quality of the beam actually acting on the surface of the test element.
Preferably, the laser system of this embodiment may further include a second beam splitting device and an energy measuring device, the second beam splitting device is configured to split the laser beam emitted by the converging device into sub-beams, and the energy measuring device is configured to measure an energy level of the sub-beams. Referring to fig. 2, thesecond beam splitter 112 is disposed on the light path exiting from the convergingdevice 102, and thesecond beam splitter 112 reflects part of the laser light to theenergy measuring device 113. Preferably, the secondlight splitting device 112 includes light splitting mirrors with a plurality of light splitting ratios, and can be switched by the electricrotating wheel 114 controlled by the computer, and the light splitting mirrors with different light splitting ratios are selected according to different test laser energy ranges of different test elements, so that the laser energy received by theenergy measuring device 113 is always within the measuring range.
The calibration method of the laser system for the laser energy spatial distribution in the embodiment is as follows: the energy distribution data of the laser beam is obtained according to the following formula:
Where M denotes a relative energy distribution of the measured laser beam, E denotes a total energy of the measured laser beam, and M' denotes actual energy distribution data of the obtained laser beam.
In the actual testing process, the beamquality monitoring device 111 triggers sampling by the light-emitting signal of thelaser generating device 100, and the spatial distribution map of the relative energy of the laser obtained by sampling is combined with the total energy of the laser obtained by sampling by theenergy measuring device 113, so as to finally obtain the spatial distribution map of the actual energy of the laser. Preferably, the beam quality data obtained by sampling the beamquality monitoring device 111 may be first background-removed, specifically when m isij<mthSeason mij0, wherein mthRepresenting a background threshold. And then according to the formula, calculating to obtain actual energy distribution data according to the background-removed light beam quality data.
Correspondingly, the embodiment also provides a laser-induced damage testing system, which comprises a laser system for projecting laser to the surface of the testing element, wherein the laser system adopts the laser system.
The laser system that the laser-induced damage test system of this embodiment adopted can adjust output laser facula size, can adjust output laser facula size according to the test demand, helps improving efficiency of software testing and test accuracy.
Further referring to fig. 2, the laser induced damage testing system of the present embodiment further includes an obtainingdevice 115, configured to obtain surface information of thetesting element 118, so as to obtain a testing result for thetesting element 118. Alternatively, the acquiringdevice 115 may adopt a camera device, and the image of the test element is acquired by the camera device. The image capture device may use a telecentric lens with magnification.
Preferably, the testing system of the present embodiment may further include anillumination device 117 for illuminating thetesting element 118 to ensure that the obtainingdevice 115 can obtain the clear and accurate surface information of thetesting element 118. Theillumination device 117 is preferably a surface light source, which is a white light source capable of providing uniform light intensity.
Preferably, the surface under test of thetest element 118 is in the focal plane of the laser system. Thetest element 118 can be fixed on the displacement table 116, and the displacement table 116 drives thetest element 118 to move, so that the laser projected by the laser system can scan and test the surface of thetest element 118. Specifically, a two-dimensional displacement table can be used to carry thetest element 118, and the two-dimensional displacement table can control thetest element 118 to move in a focal plane, so that the laser focal spots sequentially irradiate the entire test area of thetest element 118 according to a preset sequence.
Further, the embodiment of the invention also provides a laser-induced damage testing method, which uses the laser system. Referring to fig. 4, fig. 4 is a flowchart of a laser-induced damage testing method provided in this embodiment, and as can be seen from the diagram, the laser-induced damage testing method includes the following steps:
s200: when the laser generating device outputs laser, the surface information of the test point on the test element is obtained, and the first timer is triggered and started.
In each test, the light-emitting signal of the laser generating device is used as a synchronous signal for triggering. The first timer T1 sets the time for acquiring the surface information of the test point on the test element. When the laser generating device outputs laser, the first timer T1 is triggered to be started, and the surface information of the test point on the test element is acquired.
S201: and when the set time of the first timer is over, moving the next test point of the test element to the target position, and triggering and starting a second timer.
The time set by the second timer T2 is used for positioning the test point, and if the next test point needs to adjust the laser energy, the time set by the second timer T2 is used for positioning the test point and adjusting the energy control device.
The target position corresponds to a laser irradiation position projected by the laser system. When the time set by the first timer T1 is over, the second timer T2 is triggered to be started, and meanwhile, the next test point of the test element is moved to the target position through the motion of the displacement table for positioning, and the energy control device is adjusted.
S202: and when the set time of the second timer is over, judging whether the next test point of the test element reaches the target position. If yes, the process proceeds to step S203.
S203: and acquiring the surface information of the next test point on the test element, and triggering and starting a third timer.
The time set by the third timer T3 is used to acquire the surface information of the test point on the test element, and specifically used to acquire the surface information of the test point on the test element before the laser irradiation. If the next test point of the test element reaches the target position, a third timer T3 is triggered to be started, and the surface information of the next test point on the test element is obtained.
When the time set by the third timer T3 is over, one laser irradiation test is completed, and the next test can be immediately shifted to.
Preferably, referring to fig. 5, in the method of this embodiment, if it is determined in step S202 that the next test point of the test element does not reach the target position, the step S204 is executed.
S204: and blocking the laser beam generated by the laser system from projecting to the next test point of the test element.
When the time set by the second timer T2 is over, but the next test point of the test element does not reach the target position, the laser beam generated by the laser system is blocked from being projected onto the next test point of the test element to avoid being irradiated by the laser during the movement of the test element. In practical applications, the laser irradiation may be blocked by closing the shutter of the laser system.
S205: and if the next test point of the test element reaches the target position, allowing the laser beam generated by the laser system to be projected to the next test point of the test element when the set time of the next first timer is over, acquiring the surface information of the next test point on the test element and triggering to start a third timer.
After the shutter is closed, when the next test point of the test element reaches the target position, after the set time of the nearest next first timer T1 is over, the shutter is opened to allow the laser beam generated by the laser system to be projected to the next test point of the test element, and the surface information of the next test point on the test element is acquired, and at the same time, the third timer T3 is triggered.
Specifically, the working mode of each timer is a single mode, that is, the timer is automatically closed after the set time of the timer is over.
The laser-induced damage testing method of the embodiment divides one period of laser output by the laser generating device into three time periods, and realizes that the test point of the test element is moved to a target position, the test point is irradiated by laser and surface information of the test point is obtained in one light emitting period of the laser generating device, so that the testing efficiency is improved.
In a further method of this embodiment, the surface information of the test element may be obtained by acquiring an image of the surface of the test element. Optionally, a laser damage test result of the test area on the test element may be obtained according to the following method, please refer to fig. 6, where fig. 6 is a flowchart of a method for obtaining a laser damage test result of the test area on the test element according to this embodiment, and includes the following steps:
s300: and for each test point of the test area on the test element, obtaining a damage morphology image corresponding to the test point according to the images of the test point before and after being irradiated by laser.
The damage shape image corresponding to the test point is an image capable of reflecting the change of the shape of the test point after being irradiated by laser relative to the shape before being irradiated by the laser. The images of the test points before and after being irradiated by the laser can be subjected to differential processing, and then damage morphology images corresponding to the test points are obtained. In practical application, the image can be subjected to differential binarization processing.
S301: and splicing the damage appearance images corresponding to the test points of the test area. And splicing the damage appearance images corresponding to the test points in the test area to obtain an image of the whole test area including the damage appearance images of the test points.
S302: and obtaining a damage test result of the test area according to the spliced image.
And counting the total number of the test points and the number and the appearance of the damage points according to the spliced images to further obtain a damage test result, such as damage density.
Further preferably, the scanning path of the test point on the test element may be a grid-shaped path, and the scanning is performed from bottom to top, so as to avoid the influence of a broken object generated by the damage point on the untested point. Referring to fig. 7, fig. 7 is a schematic diagram of a path for scanning test points on a test area in the present embodiment, where circles represent the test points, and arrows represent a scanning route.
The laser system, the laser induced damage testing system and the laser induced damage testing method provided by the invention are described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.