CN116773147A - Laser output light spot characteristic measuring device and method - Google Patents
Laser output light spot characteristic measuring device and method Download PDFInfo
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- G—PHYSICS
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- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
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- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
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- G01M11/02—Testing optical properties
- G01M11/0207—Details of measuring devices
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- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
- G01M11/0242—Testing optical properties by measuring geometrical properties or aberrations
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- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
- G01M11/0242—Testing optical properties by measuring geometrical properties or aberrations
- G01M11/025—Testing optical properties by measuring geometrical properties or aberrations by determining the shape of the object to be tested
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Abstract
The application provides a device and a method for measuring the characteristics of output light spots of a laser, wherein the device comprises a beam splitter, a light wavelength conversion element, a refractive lens, a telecentric lens and a detection device; the beam splitter is arranged in a laser path to be measured and divides the laser to be measured into a first beam used for measuring a near-field beam and a second beam used for measuring a far-field beam; the refraction mirrors are respectively arranged along the propagation directions of the first light beam and the second light beam so as to change the length and the direction of propagation paths of the two light beams, and the first light beam and the second light beam are respectively projected to different positions on the surface of the optical wavelength conversion element; the optical wavelength conversion element converts the received first light beam and second light beam into visible light; after the telecentric lens and the detection device are sequentially provided with the optical wavelength conversion element, the telecentric lens images visible light spots of the first light beam and the second light beam on the detection device, and the detection device collects visible light spot information. The application converts the laser to be tested into visible light through the optical wavelength conversion element so as to indirectly test the light spot characteristic of the laser to be tested.
Description
Technical Field
The application relates to the technical field of lasers, in particular to a device for measuring the characteristics of output light spots of a laser.
Background
With rapid development of technology, lasers are widely used in the field of chip processing of semiconductors, and are one of the most common light source devices in the field of lithography machines. The laser spot characteristic is a core index of laser parameters of a lithography light source system and is an important factor affecting lithography imaging quality. The laser spot characteristics include spot size, which is a determining factor of the aperture size of the illumination system, and divergence angle, which is an important parameter for marking the effective transmission of the laser system, and thus are particularly important for measuring the laser spot characteristics of the laser.
At present, in order to improve the resolution of a photoetching machine, the wavelength of a corresponding laser is shorter and shorter, particularly, the wavelength of deep ultraviolet or extreme ultraviolet is used, and when the laser spot characteristic measurement is carried out under the wavelength band, a common light beam quality analyzer has no obvious signal response. The ultraviolet beam mass analyzer can only be used for testing, but in general, the ultraviolet beam mass analyzer is difficult to achieve larger size under the condition of ensuring a certain resolution. Even if the ultraviolet beam mass analyzer with the size being satisfied can be found, the price is high, and the purchasing period is long, which is a problem that cannot be ignored. Or the original excimer laser device is additionally provided with an imaging device for beam shrinking, and a corresponding calibration device is introduced on the basis of the beam shrinking, so that the energy distribution and the power of light spots of the excimer laser device under different heavy frequencies are inconsistent, the complexity of the calibration device is increased, and the calibration precision is not high.
Therefore, there is an urgent need to design a device for measuring the characteristics of output light spots of a laser, which can solve various defects introduced by an ultraviolet beam quality analyzer, and can easily realize the capability of simultaneously and orderly testing the size and the divergence angle of the light spots, thereby being convenient for data analysis.
Disclosure of Invention
The application provides a laser output light spot characteristic measuring device, which aims to solve at least one technical problem that an ultraviolet beam quality analyzer cannot synchronously measure the light spot size and the divergence angle, and has the advantages of low integration level, poor data synchronism, repeated construction of a light path, complex debugging, low efficiency and the like. The application also relates to a method for measuring the characteristics of the laser output light spots.
The application provides a laser output light spot characteristic measuring device, which comprises: the device comprises a beam splitter, a light wavelength conversion element, a refractive lens, a telecentric lens and a detection device;
the beam splitter is arranged in the laser path of the laser to be measured and is used for dividing the laser to be measured into a first beam used for measuring a near-field beam and a second beam used for measuring a far-field beam;
the refraction mirrors are respectively arranged along the propagation directions of the first light beam and the second light beam so as to change the length and the direction of the propagation paths of the two light beams, and the first light beam and the second light beam are respectively projected to different positions on the surface of the optical wavelength conversion element; the optical wavelength conversion element is used for converting the received first light beam and the received second light beam into visible light;
the telecentric lens and the detection device are sequentially arranged behind the optical wavelength conversion element along the optical path, the telecentric lens is used for imaging visible light spots of the first light beam and the second light beam on the detection device, and the detection device is used for collecting information of the visible light spots.
In one implementation, a first optical attenuator is disposed before the beam splitter, where the first optical attenuator is used to attenuate the laser to be measured.
In one implementation, a focusing lens is further disposed behind the beam splitter along a propagation direction of the second light beam, and the second light beam is converged at a focal point of the focusing lens.
In one implementation, the size of the beam splitter is determined according to parameters of the laser to be measured.
In one implementation, the first optical attenuator, the beam splitter, the focusing lens, and the fold mirror are disposed in a test case.
In one implementation, the light wavelength conversion element and the telecentric lens are located in a sealed arrangement.
In one implementation, the telecentric lens is an object-side telecentric lens, or an image-side telecentric lens.
In one implementation, the optical wavelength conversion element comprises a fluorescent glass or a fluorescent conversion crystal.
In one implementation, the detection device is a camera, which is coupled to the telecentric lens.
The application also provides a method for measuring the characteristics of the laser output light spots, which uses any one of the feasible laser output light spot characteristics measuring devices for measurement.
Compared with the prior art, the application has the following advantages:
according to the application, the laser to be tested is divided into the first beam used for measuring the near-field beam and the second beam used for measuring the far-field beam through the beam splitter, and the first beam and the second beam are respectively converted into visible light through the optical wavelength conversion element, so that the spot characteristics of the laser to be tested are indirectly tested, the capability of simultaneously testing the near-field spot size and the far-field divergence angle is provided, and the data analysis and the problem investigation are facilitated.
Drawings
FIG. 1 is a schematic diagram of a laser output spot property measuring apparatus according to a first embodiment of the present application;
FIG. 2 is a schematic diagram of a method for testing the spot size characteristics of a laser in a first embodiment of the present application;
FIG. 3 is a schematic diagram of a method for testing divergence angle characteristics of a laser in a first embodiment of the present application;
reference numerals:
100: a beam splitter;
200: a light wavelength conversion element;
300: a first refractor; 300-2: a second refractive mirror; 300-3: a third refractive lens; 300-4: a fourth fold mirror; 300-5: a fifth refractive mirror;
400: a telecentric lens;
500: a detection device;
600: a laser light source to be measured;
700: a first optical attenuator; 700-2: a second optical attenuator;
800: a focusing lens.
Detailed Description
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than those herein described, and those skilled in the art will readily appreciate that the present application may be similarly embodied without departing from the spirit or essential characteristics thereof, and therefore the present application is not limited to the specific embodiments disclosed below.
In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.
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 at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "configured," "connected," "secured," and the like are to be construed broadly and include, for example, either permanently connected, removably connected, or integrally formed; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
In the related art, when related data of the spot size and the divergence angle of a laser are measured, the spot size and the divergence angle of the laser are often required to be measured through an ultraviolet beam mass analyzer, and the spot size and the divergence angle are required to be separately and independently tested, so that the measuring device is low in integration level, complicated to use and low in efficiency. In view of the above, the present application provides a device for measuring characteristics of output light spots of a laser, which comprises a beam splitter, a light wavelength conversion element, a beam splitter, a telecentric lens and a detection device; the beam splitter is arranged in the laser path of the laser to be measured and is used for dividing the laser to be measured into a first beam used for measuring a near-field beam and a second beam used for measuring a far-field beam; the refraction mirrors are respectively arranged along the propagation directions of the first light beam and the second light beam so as to change the length and the direction of the propagation paths of the two light beams, and the first light beam and the second light beam are respectively projected to different positions on the surface of the optical wavelength conversion element; the optical wavelength conversion element is used for converting the received first light beam and the received second light beam into visible light; the telecentric lens and the detection device are sequentially arranged behind the optical wavelength conversion element along the optical path, the telecentric lens is used for imaging visible light spots of the first light beam and the second light beam on the detection device, and the detection device is used for collecting information of the visible light spots.
In other words, the first light beam and the second light beam of the laser to be tested are converted into visible light through the light wavelength conversion element, the light spot characteristics of the laser to be tested are indirectly tested through testing the light spot characteristics of the visible light, the capability of testing the light spot size and the divergence angle of the laser to be tested simultaneously and sequentially is provided, and data analysis and problem investigation are facilitated.
While alternative implementations of the application are described below with reference to the accompanying drawings, it will be understood by those skilled in the art that the implementations described below are illustrative only and not an exhaustive list, and that those skilled in the art may substitute, splice, or combine certain features or certain examples based on these implementations, and still be considered as the disclosure of the application.
A first embodiment of the present application will be described in detail with reference to fig. 1 to 3.
Fig. 1 is a schematic diagram of a device for measuring characteristics of output light spots of a laser according to an embodiment of the present application. The laser output light spot characteristic measuring device comprises a beam splitter 100, a light wavelength conversion element 200, a refraction mirror, a telecentric lens 400 and a detecting device 500.
As shown in fig. 1, a laser light source 600 to be measured is located at the front end of the laser output spot feature measuring device, and is used for providing laser light to be measured.
Since the energy of the laser to be measured is strong, in order to avoid damage to the optical wavelength conversion element 200 and the detection device 500 by the laser to be measured, the received laser to be measured is attenuated by the first optical attenuator 700. The first optical attenuator 700 is disposed after the laser light source 600 to be measured and before the beam splitter 100.
The material of the first optical attenuator 700 may be fused silica or calcium fluoride (CaF 2).
In a specific embodiment, the degree of energy attenuation of the laser light to be measured by the first optical attenuator 700 may be adjusted by:
the first way is: the angle of the laser to be measured entering the first optical attenuator 700 is adjusted by adjusting the angle of the first optical attenuator 700, so as to realize the adjustment of the energy attenuation degree of the laser to be measured.
The second way is: by varying the number of first optical attenuators 700, the energy of the laser light to be measured is attenuated. The number of the first optical attenuators 700 is set according to the laser attenuation energy to be measured. In the embodiment of the present application, a first optical attenuator 700 is disposed after the laser light source 600 to be tested, but the implementation of disposing a greater number of optical attenuators in the subsequent optical path to enhance the attenuation effect of the laser is not excluded. In addition, in the embodiment using a plurality of optical attenuators, the angles of the different optical attenuators may be the same or different, and the present application is not limited thereto.
The above-listed adjustment manner attenuates the energy of the laser to be measured by the first optical attenuator 700, so that the energy of the attenuated laser to be measured can meet the requirements of the subsequent optical wavelength conversion element 200 and the detection device 500. The first optical attenuator 700 may be configured to manually adjust the angle or the number of the first optical attenuators, or may be configured to automatically adjust the angle or the number of the first optical attenuators, which is not limited herein.
In this embodiment, the beam splitter is disposed in the optical path of the laser to be measured. When the laser light to be measured attenuated by the first optical attenuator 700 enters the beam splitter 100, the beam splitter 100 splits the laser light to be measured into a first beam for near-field beam measurement and a second beam for far-field beam measurement.
The near-field beam measuring device is used for measuring the first beam in the near-field beam measuring device, and is used for measuring the spot size of the laser to be measured; and the second beam in the far-field beam measuring device is used for measuring the divergence angle of the laser to be measured.
The beam splitter 100 may be a substrate without a coating film, or may be a coated lens having various beam splitting ratios, and the material thereof may be fused silica or calcium fluoride (CaF 2), and the specific structure and material of the beam splitter 100 are not limited.
The size of the beam splitter 100 is determined according to parameters of the laser to be measured, such as wavelength and spot size of the laser to be measured. Specifically, the thickness d of the beam splitter 100 may be determined by the incident angle θ, the spot size h, and the refractive index n of the laser to be measured, and the specific formula is:
it can be understood that when the thickness of the beam splitter 100 satisfies the above formula, the laser to be measured entering the beam splitter 100 can be thoroughly split into the first beam and the second beam under the condition that the incident angle of the laser to be measured is θ. Specifically, when the laser to be measured is incident on the beam splitter 100, the front surface (the surface that contacts the beam splitter 100 when the laser to be measured is incident) and the rear surface (the surface that leaves the beam splitter 100 when the laser to be measured is transmitted) of the beam splitter 100 reflect the laser. The light reflected by the front surface is used as the second light beam to measure the far-field divergence angle, the light reflected by the rear surface is used as the non-light and is absorbed by the foamed aluminum or the light barrier, and the transmitted light passing through the beam splitter 100 is used as the first light beam to measure the near-field spot size, so that the laser to be measured is thoroughly split into the first light beam and the second light beam.
The incident angle of the laser to be measured determines the propagation direction of the second beam after being separated. In the implementation process, the incident angle of the laser to be measured can be adjusted by changing the installation angle of the beam splitter 100. And, the propagation direction of the second light beam may be made to coincide with a preset propagation direction of the second light beam by adjusting the installation angle of the beam splitter 100. Of course, the propagation direction of the second light beam may be adjusted by the refraction mirror so as to be consistent with the preset propagation direction of the second light beam, which is not limited herein.
The thickness of the beam splitter 100 may be determined according to different requirements. For example, the thickness of the beam splitter 100 may be determined according to the upper limit value of the spot size index, so that the beam splitter 100 can split all the lasers to be measured that meet the spot size index, and thus the beam splitter 100 can meet the beam splitting requirement of the excimer laser.
In addition, it should be noted that, in the embodiment of the present application, the principle of splitting light to be measured by the beam splitter 100 is calculated according to the damage threshold of the detector, so as to ensure that the detector is not damaged in the measurement process.
The measuring device of each of the near-field light beam (first light beam) and the far-field light beam (second light beam) will be described in detail.
As shown in fig. 1, a refractive mirror is disposed along the propagation direction of the first light beam and the second light beam, respectively, to change the length and direction of the propagation paths of the two light beams, and to project the first light beam and the second light beam to different positions on the surface of the optical wavelength conversion element 200.
The space volume of the measuring device can be compressed by turning the propagation paths of the first light beam and the second light beam through the arranged folding mirrors, so that the portability of the whole testing device is improved.
In the embodiment of the application, the paths and the turning directions of the first light beam and the second light beam can be changed by adjusting the angle of the refraction mirror, so that the adjusted angle of the refraction mirror can meet the propagation requirements of the first light beam and the second light beam. It should be noted that the number of the refraction mirrors is not excessively limited, and the number of the refraction mirrors can be increased according to the requirement in the actual working process.
Wherein, the material of the refraction mirror can be a high-reflection mirror coated with a dielectric film or a metal film.
On the second beam propagation path, a focusing lens 800 is further disposed behind the beam splitter 100, and the focusing lens 800 converges the received second beam, so that the converged second beam is focused at the focal point of the focusing lens 800.
In this embodiment, after the focusing lens 800 focuses the second light beam, the second light beam is finally projected onto the optical wavelength conversion element 200 to measure the divergence angle of the laser to be measured. Wherein the light distance between the second light beam from the focusing lens 800 to the optical wavelength conversion element 200 is the focal length at which the second light beam is focused, and corresponds to the spot of the second light beam projected onto the optical wavelength conversion element 200.
Since the same optical medium has different refractive indexes for light of different wavelengths, the focal length at which the focusing lens 800 focuses may be different for light of different wavelengths. In a practical implementation process, the light distance propagated by the second beam focusing process can be changed by adjusting the number, the position and the angle of the refractive lenses between the focusing lens 800 and the optical wavelength conversion element 200, so that the divergence angle obtained by measurement is more accurate.
In addition, the focusing lens 800 may be set as a lens with a larger focal length, so that it is ensured that the focal point of the focusing lens 800 falls on the optical wavelength conversion element 200 or behind the optical wavelength conversion element 200 for light with different wavelengths, thereby reducing measurement errors, and improving measurement accuracy. The focusing lens 800 may be made of calcium fluoride, fused silica, or the like, and is not limited thereto.
The optical wavelength conversion element 200 is configured to convert the received first light beam and the received second light beam into visible light, respectively. It is understood that when the first light beam and the second light beam propagate to different positions on the surface of the optical wavelength conversion element 200, the optical wavelength conversion element 200 converts the received first light beam and second light beam into visible light, respectively.
The optical wavelength conversion element 200 may be fluorescent glass or a fluorescent conversion crystal. The optical wavelength conversion element 200 emits visible light fluorescence by the effect of the laser to be measured and the fluorescent substance, and the wavelength of the emitted visible light fluorescence can be realized by changing the ion type or ion concentration doped in the optical wavelength conversion element 200, which is not limited herein. In this embodiment of the present application, the laser to be tested may be ultraviolet light, that is, the optical wavelength conversion element 200 converts the first light beam (ultraviolet light) and the second light beam (ultraviolet light) into visible light at the same time, so as to indirectly test the spot characteristics of the laser to be tested (ultraviolet light) by testing the spot characteristics of the visible light.
In addition, the responsiveness of the common camera to visible light is high, so that the measurement of the light spot characteristics can be realized by adopting the common camera. Meanwhile, the common camera does not have a chopping wave plate, so that the problem that the chopping wave plate rotating at a fixed frequency collects useless data in a laser gap is avoided, and the measured data can truly reflect the state of the laser. In recent years, the domestic cameras have wide markets, the resolution is generally higher than that of ultraviolet cameras, and the problems of high cost and long period of an ultraviolet beam quality analyzer can be solved. Compared with ultraviolet light, the visible light converted by the optical wavelength conversion element 200 has longer wavelength and lower photon energy, so that the damage to the camera is lower, the risk of damage to the ultraviolet camera is avoided, and the service life is prolonged.
The operation principle of the optical attenuator 700, the beam splitter 100, the focusing lens 800, and the folding mirror is described in detail. In addition, in order to improve the accuracy of measurement, the optical attenuator 700, the beam splitter 100, the focusing lens 800, and the folding mirror may be disposed in a test case filled with high purity nitrogen gas to improve the measurement effect. And can set up first through-hole in the bottom of test box body, make nitrogen gas enter into the test box body through first through-hole.
The first light beam and the second light beam are turned over by the refraction mirrors on the respective paths, and after coming out from the test box body, the first light beam and the second light beam enter the surface of the optical wavelength conversion element 200, and the optical wavelength conversion element 200 converts the first light beam and the second light beam into visible light spots.
In this embodiment, after the first light beam and the second light beam pass through the optical wavelength conversion element 200, they enter the telecentric lens 400.
After the telecentric lens 400 and the detecting device 500 are sequentially disposed on the optical wavelength conversion element 200, the telecentric lens 400 is used for imaging the visible light spots of the first light beam and the second light beam on the detecting device 500, and the detecting device 500 is used for collecting information of the visible light spots.
Wherein the optical wavelength conversion element 200 and the telecentric lens 400 are located in a sealed device. In the embodiment of the present application, telecentric lens 400 is fixed on the sealing device by threads, but other fixing methods are not excluded, for example: bolt fixing, buckle fixing, flange fixing and other modes.
In addition, in the embodiment of the application, the flange can be used for fixedly connecting the test box body and the sealing device, but other connection modes can also be used, for example: the connection modes such as threaded connection, snap connection, welding, etc. are not limited herein.
It should be clear that, when the distance between the telecentric lens 400 and the optical wavelength conversion element 200 satisfies the working distance of the telecentric lens 400, the visible light spots of the first beam and the second beam on the optical wavelength conversion element 200 are imaged on the detecting device 500 by the telecentric lens 400 according to a certain proportion. The working distance of the telecentric lens 400 is determined by the model of the telecentric lens 400, and the working distance is different for different telecentric lenses 400.
In addition, the luminous flux of the telecentric lens 400 can be controlled by adjusting the aperture size of the lens, so that repeated debugging steps of the optical attenuator 700 under different heavy frequencies are avoided, and the advantages of high test integration level, simplicity in debugging, high efficiency, improvement of precision and the like are realized.
In the embodiment of the present application, telecentric lens 400 may be an object-side telecentric lens or an image-side telecentric lens, and the selection of telecentric lens 400 may be determined according to the actual working condition, which is not limited herein.
The telecentric lens 400 has the characteristic that the imaging multiple is fixed within a certain working distance range, solves the problem of imaging size change caused by object distance change of a conventional imaging lens, avoids the complexity of repeated calibration under different repetition frequencies, greatly improves the measurement accuracy, simultaneously has relatively smaller distortion and small aberration of the telecentric lens 400, can relatively truly reflect the laser spot characteristics, reduces the optimization operation of a plurality of column algorithms caused by image quality influence during image processing, and improves the measurement accuracy.
In addition, in order to reduce the influence of stray light on the sealing device, a light adsorption device can be further arranged in the sealing device, so that the stray light in the sealing device is adsorbed.
In this embodiment, the detection device 500 is located at the image plane of the telecentric lens 400. The telecentric lens 400 images on the detecting device 500 in a certain proportion, and the detecting device 500 can collect light spot images under different heavy frequencies without damaging sealing by adjusting the aperture size of the telecentric lens 400, and correspondingly calculate and process according to the collected images, so that the size of the light spot size and the size of the divergence angle are obtained, and the purpose of simultaneously testing the size of the light spot and the size of the divergence angle in sequence is achieved.
In the embodiment of the present application, the detecting device 500 is a camera, and the camera is connected with the telecentric lens 400 in a matching way. The interface of the camera and the telecentric lens 400 may be in the form of a C interface, an F interface, a CS interface, or the like, and the interface of the telecentric lens 400 is in a sealed state. When a camera is connected to the interface of telecentric lens 400, the type of interface to be connected may be selected according to the model of the camera. The camera may be a CCD camera or a CMOS camera, which is not limited herein.
Next, the test principle of the first light beam and the second light beam will be described in detail.
The principle of testing the first beam is shown in fig. 2, and fig. 2 is a schematic diagram of a method for testing the spot size characteristics of a laser, where a feasible transmission path of the first beam is shown, and the spot size characteristics of a near field of the laser to be tested are measured according to the transmission path. As can be seen in connection with fig. 2, the transmission path of the first light beam is: the device comprises a laser light source 600 to be tested, a first optical attenuator 700, a beam splitter 100, a first refractor 300, an optical wavelength conversion element 200, a telecentric lens 400 and a detection device 500. After the laser to be measured emitted by the laser to be measured light source 600 passes through the first optical attenuator 700, the first optical attenuator 700 attenuates the energy of the laser to be measured, the laser to be measured after attenuation irradiates the beam splitter 100, the beam splitter 100 splits the laser to be measured into two beams, the beam projected by the beam splitter 100 is the first beam, the first beam reaches the first refractive mirror 300, and the first refractive mirror 300 adjusts the length and direction of the propagation path of the first beam, so that the first refractive mirror 300 can accurately refract the light to the surface of the optical wavelength conversion element 200.
The laser light source 600 to be measured is located at the front end of the laser light path to be measured and is used for emitting laser to be measured, and in a preferred embodiment, the laser light source 600 to be measured emits ultraviolet light, which has the characteristics of shorter wavelength, larger photon energy and the like, so that the measurement effect is better. Correspondingly, when the laser light source 600 to be tested emits ultraviolet light, the first optical attenuator 700 attenuates the emitted ultraviolet light.
Measurement of the second beam is shown in fig. 3, and fig. 3 is a schematic diagram of a method for testing divergence angle characteristics of a laser, where a feasible transmission path of the second beam is shown, and the divergence angle characteristics of a far field of the laser to be tested are measured according to the transmission path. Referring to fig. 3, it can be seen that the second light beam sequentially passes through the first optical attenuator 700, the beam splitter 100, the focusing lens 800, the second refractive lens 300-2, the second optical attenuator 700-2, the third refractive lens 300-3, the fourth refractive lens 300-4, the fifth refractive lens 300-5, the optical wavelength conversion element 200, the telecentric lens 400, and the detecting means 500 along the propagation direction.
As shown in fig. 2, after the laser light source 600 emits the laser light to be measured, the laser light to be measured is energy-attenuated by the first optical attenuator 700, and then is split into the second beam by the beam splitter 100. The second beam enters the focusing lens 800 and the spot is focused at its focal point by the focusing lens 800. Wherein the second refractive lens 300-2, the third refractive lens 300-3, the fourth refractive lens 300-4 and the fifth refractive lens 300-5 arranged behind the focusing lens 800 are used to change the propagation direction of the second light beam such that the second light beam is projected on the light wavelength conversion element 200.
In the specific propagation process of the second light beam shown in fig. 3, the second light beam enters the second refractive lens 300-2, the second light beam is folded by the second refractive lens 300-2 and then enters the second optical attenuator 700-2, the energy of the second light beam is attenuated again by the second optical attenuator 700-2, and after the attenuated second light beam meets the requirement, the second light beam enters the refractive mirrors (namely, the third refractive lens 300-3, the fourth refractive lens 300-4 and the fifth refractive lens 300-5) again and is refracted onto the surface of the optical wavelength conversion element 200.
In an embodiment of the present application, the selection of the number of second optical attenuators 700-2 is determined based on the magnitude of the energy of the second beam. In addition, the number of the refraction mirrors is selected based on that the length and the direction of the propagation path of the laser to be tested (the first beam and the second beam) are adjusted through the refraction mirrors, so that the laser can be accurately refracted onto the surface of the optical wavelength conversion element 200.
In addition, after the telecentric lens 400 and the detecting device 500 are sequentially disposed on the optical wavelength conversion element 200 along the optical path, the telecentric lens 400 is used for imaging visible light spots of the first light beam and the second light beam on the detecting device 500, and the detecting device 500 is used for collecting information of the visible light spots, so that a measurement structure can be obtained according to the spot information.
When measuring the divergence angle of the laser to be measured, the divergence angle is obtained by calculating the size of a light spot at a focus and the focal length of a focusing lens. The calculation formula is as follows:
wherein W is the size of a light spot at the focus;
f is the focal length of the focusing lens.
The light path in the embodiment of the application enables the near-field light beam and the far-field light beam to enter the light wavelength conversion element 200 through the beam splitter 100 and the beam splitter, and to be distributed on two sides, and then to be imaged on a camera at an image plane through the telecentric lens 400 according to a certain proportion, and the two visible light spots collected by the camera are correspondingly processed and calculated, so that the spot size and the divergence angle of the laser can be synchronously obtained, and the functions of collecting and displaying the near-field light spot characteristics and the far-field light spot characteristics at the same time sequence are realized. Meanwhile, in the embodiment of the application, the method for adjusting the aperture size of the telecentric lens 400 is adopted to control the luminous flux, so that the repeated debugging step of the attenuator under different repetition frequencies is omitted, and the advantages of high test integration level, simple debugging, high efficiency, high precision and the like are realized.
By the introduction, it can be seen that the device for measuring the characteristics of the output light spot of the laser provided by the embodiment of the application not only solves the practical problems of high cost, long period, easy damage and the like of the ultraviolet beam quality analyzer, but also avoids the problem that the collected data of the ultraviolet beam quality analyzer contains useless data in the intermittent laser, and simultaneously realizes the capability of testing the near-field light spot size and the far-field divergence angle with time sequence on the light path design and software.
In addition, a second embodiment of the present application provides a method for measuring characteristics of an output spot of a laser, including: the measurement is performed using any one of the aforementioned possible laser output spot property measuring devices. The method for measuring the characteristics of the output light spot of the laser corresponds to the device for measuring the characteristics of the output light spot of the laser, and detailed description thereof will not be made herein.
While the application has been described in terms of preferred embodiments, it is not intended to be limiting, but rather, it will be apparent to those skilled in the art that various changes and modifications can be made herein without departing from the spirit and scope of the application as defined by the appended claims.
Claims (10)
1. A laser output spot characteristic measuring apparatus, comprising: the device comprises a beam splitter, a light wavelength conversion element, a refractive lens, a telecentric lens and a detection device;
the beam splitter is arranged in a laser path to be measured and is used for dividing the laser to be measured into a first beam used for measuring a near-field beam and a second beam used for measuring a far-field beam;
a folding mirror is respectively arranged along the propagation direction of the first light beam and the second light beam so as to change the length and the direction of the propagation paths of the two light beams, and the first light beam and the second light beam are respectively projected to different positions on the surface of the optical wavelength conversion element; the optical wavelength conversion element is used for converting the received first light beam and the received second light beam into visible light;
the telecentric lens and the detection device are sequentially arranged behind the optical wavelength conversion element along an optical path; the telecentric lens is used for imaging visible light spots of the first light beam and the second light beam on the detection device; the detection device is used for collecting information of the visible light spots.
2. The laser output spot characteristic measuring apparatus according to claim 1, wherein a first optical attenuator for attenuating the laser light to be measured is provided before the beam splitter.
3. The laser output spot property measuring apparatus according to claim 2, wherein a focusing lens is further provided after the beam splitter in a propagation direction of the second light beam, the second light beam converging at a focal point of the focusing lens.
4. The device for measuring the characteristics of output light spots of a laser according to claim 1, wherein the size of the beam splitter is determined according to the parameters of the laser to be measured.
5. The laser output spot property measuring apparatus according to claim 2, wherein the first optical attenuator, the beam splitter, the focusing lens, and the refractive lens are disposed in a sealed test case.
6. The laser output spot property measuring apparatus of claim 1 wherein the optical wavelength conversion element and the telecentric lens are located in a sealing apparatus.
7. The laser output spot property measuring apparatus of claim 1 wherein the telecentric lens is an object side telecentric lens or an image side telecentric lens.
8. The laser output spot property measuring apparatus according to claim 1, wherein the optical wavelength conversion element comprises a fluorescent glass or a fluorescent conversion crystal.
9. The laser output light spot characteristic measuring apparatus according to claim 1, wherein the detecting means is a camera, and the camera is connected to the telecentric lens in a matched manner.
10. A method of measuring the output spot characteristics of a laser, characterized in that the measurement is performed using the laser output spot characteristic measuring apparatus according to any one of claims 1 to 9.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117470390A (en) * | 2023-12-28 | 2024-01-30 | 深圳市柠檬光子科技有限公司 | Laser testing device and laser testing method |
| CN118550095A (en) * | 2024-07-24 | 2024-08-27 | 北京大学 | Optical path adjusting device, optical path adjusting method thereof and laser |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117470390A (en) * | 2023-12-28 | 2024-01-30 | 深圳市柠檬光子科技有限公司 | Laser testing device and laser testing method |
| CN117470390B (en) * | 2023-12-28 | 2024-04-02 | 深圳市柠檬光子科技有限公司 | Laser testing device and laser testing method |
| CN118550095A (en) * | 2024-07-24 | 2024-08-27 | 北京大学 | Optical path adjusting device, optical path adjusting method thereof and laser |
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