CN102095688B - Equipment for measuring laser performance of material - Google Patents

Abstract

The invention relates to a measuring device for laser properties of materials, which includes at least one laser light source, a proportional beam splitter is arranged on the main optical axis of the laser light source, and a rotatable sample stage or The second laser energy detector that can rotate around the sample stage is equipped with the first laser energy detector on the auxiliary transmission optical path; the reflection optical path of the sample stage is provided with a mirror, and the laser reflected by the material on the sample stage is reflected to the In the second laser energy detector; the data processor adjusts and controls the output power of the laser light source according to the laser energy signal of the laser light source detected by the first laser energy detector; the data processor controls the laser energy detected by the second laser energy detector After signal processing, the corresponding material laser reflection energy angle distribution characteristics are stored and output. The invention has the advantages of simple and compact structure, high degree of automation, high measurement precision, convenient use, wide application range, safety and reliability.

Description

A measuring device for laser properties of materials

technical field

The invention relates to a measurement device, especially a measurement device for the laser performance of materials, specifically, an automatic indoor measurement device capable of performing automatic indoor measurement of the angular distribution characteristics, spectral characteristics and polarization characteristics of the laser reflection energy of materials, which belongs to laser measurement technical field.

Background technique

Laser has excellent monochromaticity, directivity and coherence, and is widely used in military ranging, weapon guidance, target recognition and reconnaissance detection and other fields. The measurement of reflection, polarization and other transmission characteristics of incident laser light on natural background objects such as vegetation, rocks, water bodies, and artificial materials such as metal surfaces, fabrics, and paint coatings is of great significance for the research of target characteristics and related material technology research.

At present, the measurement of laser properties of materials at home and abroad is basically based on field experimental methods, such as the extinction test method of laser reflection measurement [National Military Standard GJB2241A-2008, and ANSI C136.20-2008], polarimeter or polarization imaging Test [national standard GB/T 14077-1993, and MIL-13830A, ANSI/TIA455-201-2001]; indoor measurement is mainly to manually build a measurement optical path table, under the condition of vertical incidence of laser (or linearly polarized laser), measure the material For the reflected power, spectral wavelength, or polarization state of the reflected energy in the normal direction of the surface, the integration of the device is low, the debugging is more complicated, the measurement accuracy is not high, and the degree of automation is low. At present, the instrument and equipment that can complete the measurement of the characteristics of the laser reflection energy with the angular distribution has not been reported; the automatic indoor measurement device that integrates the measurement functions of the laser reflection angle distribution characteristics, spectral characteristics and polarization characteristics of materials is still blank at home and abroad. .

Contents of the invention

The object of the present invention is to overcome the deficiencies in the prior art and provide a measuring device for laser properties of materials, which has a simple and compact structure, a high degree of automation, high measurement accuracy, convenient use, wide application range, and safety and reliability.

According to the technical solution provided by the present invention, the measuring equipment for the laser properties of materials includes at least one laser light source, a proportional beam splitter is arranged on the main optical axis of the laser light source, and the main transmission optical path of the proportional beam splitter is The main measurement optical path formed by the second laser energy detector and the rotatable sample stage or the main measurement optical path formed by the second laser energy detector and the sample stage that can rotate around the sample stage; The first laser energy detector for monitoring the stability of the emission power of the light source; a reflector is arranged on the reflection optical path of the sample stage, and the laser light reflected by the material on the sample stage is reflected into the second laser energy detector through the reflector, and the first laser The output ends of the energy detector and the second laser energy detector are connected with the data processor; the data processor adjusts and controls the output power of the laser light source according to the laser energy signal of the laser light source detected by the first laser energy detector, so that the laser light source The output power is kept stable; after the data processor processes the laser energy signal detected by the second laser energy detector, it stores and outputs the corresponding angular distribution characteristics of the laser reflected energy of the material.

A polarizer is provided between the proportional beam splitter and the sample stage; an analyzer matching the polarizer is arranged between the sample stage and the reflector; the light beam of the main optical axis of the laser light source passes through the proportional beam splitter, the polarizer After being input to the material on the sample stage, the laser reflected by the material on the sample stage is reflected into the second laser energy detector after passing through the analyzer and mirror; the data processor detects the laser energy signal detected by the second laser energy detector Process, store and output the corresponding material laser polarization properties.

A spectrometer for detecting the spectral characteristics of the reflected laser light is provided on the transmission optical path between the reflecting mirror and the second laser energy detector, and the output end of the spectrometer is connected to a data processor, and the data processor processes the spectral characteristic signal input by the spectrometer, stores And output the spectral characteristics of the corresponding material reflected laser.

The data processor includes a single-chip microcomputer and an industrial computer, and the industrial computer is connected with the first laser energy detector and the second laser energy detector through the single-chip computer.

The laser light source includes four semiconductor pump laser emitters arranged in parallel, and the laser emitters are installed on the guide rail.

The laser wavelength output by the laser light source is 532nm, 650nm, 980nm or 1064nm. The sample stage is an insert type sample stage. The polarizer and analyzer are Glan-Taylor prisms.

The material of the proportional beamsplitter includes quartz, and the proportional beamsplitter splits 5% of the energy emitted by the laser light source into the laser energy detector, and the laser energy detector inputs the energy detected by the proportional beamsplitter into the data processor , the data processor controls the output of the laser light source according to the split energy signal detected by the laser energy detector, so as to keep the output power of the laser light source stable.

The rotation of the sample stage and the second laser energy detector is driven by a stepping motor.

Advantages of the present invention: a laser light source, a proportional beam splitter, a polarizer, an analyzer, a sample stage, a mirror, a laser energy detector, a spectrometer, and a detector electric control console are simultaneously installed in the casing, and the laser polarization of the material can be measured simultaneously. Characteristics, material laser energy reflection angle distribution characteristics and material spectral characteristics, high degree of integration, simple installation and debugging; the laser wavelength of the laser source can be selected, the sample stage can be rotated, and the laser energy detector can rotate around the sample stage, which improves the material The reliability of the measurement of the distribution characteristics of the laser energy reflection angle is high in automation. The whole device is controlled by the data processor and the stepping motor correspondingly. The measurement accuracy is high, the scope of application is improved, and it is safe and reliable.

Description of drawings

Fig. 1 is a structural block diagram of the present invention.

Fig. 2 is a measurement flow chart of the present invention.

Fig. 3 is the Cartesian coordinate graph of embodiment 1.

FIG. 4 is a polar coordinate graph of light detection reflection energy distribution in Embodiment 1. FIG.

FIG. 5 is a polar coordinate graph of the monitored energy of the laser light source in Embodiment 1. FIG.

FIG. 6 is a polar coordinate graph showing the difference between FIG. 4 and FIG. 5 .

Fig. 7 is the Cartesian coordinate graph of embodiment 2.

FIG. 8 is a polar coordinate graph of light detection reflection energy distribution in Embodiment 2. FIG.

FIG. 9 is a polar coordinate graph of the monitored energy of the laser light source in Embodiment 2. FIG.

FIG. 10 is a differential polar coordinate graph of FIG. 8 and FIG. 9 .

Fig. 11 is the Cartesian coordinate graph of embodiment 3.

FIG. 12 is a polar coordinate graph of light detection reflection energy distribution in Embodiment 3. FIG.

FIG. 13 is a polar coordinate graph of the monitored energy of the laser light source in Embodiment 3. FIG.

FIG. 14 is a polar coordinate graph showing the difference between FIG. 12 and FIG. 13 .

Detailed ways

The present invention will be further described below in conjunction with specific drawings and embodiments.

As shown in Figure 1: the present invention includes a laser light source 1, a guide rail 2, a proportional beam splitter 3, a polarizer 4, an analyzer 5, a sample stage 6, a mirror 7, a first laser energy detector 8, a second laser Energy detector 9 , spectrometer 10 , detector electric console 11 and data processor 12 .

As shown in Figure 1: In order to measure the angular distribution characteristics, spectral characteristics and polarization characteristics of the laser reflection energy of the material at the same time in the room, a laser light source 1 is installed in the housing, and the laser light source 1 is installed on the guide rail 2. The light source 1 can move along the guide rail 2, and the movement of the guide rail 2 is controlled by a stepping motor. The laser light source 1 includes at least one semiconductor pump laser emitter. The wavelength of laser light emitted by the laser light source 1 includes 532nm, 650nm, 980nm or 1064nm; the four semiconductor pump laser emitters can respectively output laser light of corresponding wavelengths. A proportional beam splitter 3 is arranged on the main optical axis of the laser light source 1 , and the laser light emitted by the laser light source 1 passes through the proportional beam splitter 3 and is output. When lasers of different wavelengths are needed, the guide rail 2 moves under the action of the stepping motor, so that the main axis of the corresponding laser on the guide rail 2 corresponds to the proportional beam splitter 3; the proportional beam splitter 3 can transmit 5% of the energy emitted by the laser light source 1 Transmitted into the first laser energy detector 8, the energy of the laser light source 1 is detected by the first laser energy detector 8, and the energy signal of the detection laser light source 1 is input into the data processor 12 by the first laser energy detector 8, and the data The processor 12 controls the output of the laser light source 1 to ensure the stability of the output power of the laser light source 1; the proportional beam splitter 3 transmits the remaining energy of the laser light source 1 to the material on the sample stage 6, and the sample stage 6 is an insert type The sample stage, the sample stage 6 can rotate from 0° to 180°, and the rotation of the sample stage 6 is controlled by a stepping motor. The material on the sample stage 6 reflects the laser output from the proportional beam splitter 3 to the second laser energy detector 9 through the mirror 7, and the second laser energy detector 9 inputs the laser energy signal reflected by the material on the sample stage 6 into the data In the processor 12, the data processor 12 can store and output the corresponding angular distribution characteristics of the laser reflection energy of the material after the data processor, and the angular distribution characteristics of the laser reflection energy of the material are expressed in the form of curves. The second laser energy detector 9 is installed on the detector electric console 11, and the second laser energy detector 9 can follow the rotation of the detector electric console 11; the second laser energy detector 9 can follow the detector electric console 11 to circle The sample stage 6 rotates from 0° to 180°, thereby realizing the multi-angle and multi-directional measurement of the laser reflection energy on the sample stage 6 . During specific implementation, the main transmission optical path of the ratio beam splitter 3 passes through the rotation of the sample stage 6 and the second laser energy detector 9 to form the main measurement optical path, or the second laser energy detector 9 rotates around the sample stage 6 and connects with the sample stage. 6 corresponds to the main measurement optical path formed after matching.

In order to be able to measure the polarization characteristics of the material, a polarizer 4 is arranged between the proportional beam splitter 3 and the sample stage 6, and an analyzer 5 is arranged between the sample stage 6 and the reflector 7, and the analyzer 5 is connected to the polarizer. The polarizer 4 is adjusted from zero to a certain angle; when the laser light source 1 emits laser light, it is incident on the material on the sample stage 6 after being polarized by the polarizer 4, and the material passes through the analyzer 5 and the mirror after reflection 7 is reflected in the second laser energy detector 9, the second laser energy detector 9 can detect the laser energy signal after polarization, and input the laser energy signal after polarization into the data processor 12, and the data processor 12 is to the signal After processing, the corresponding material laser polarization characteristics can be stored and output, and the material laser polarization characteristics are also expressed in the form of curves. Both the polarizer 4 and the analyzer 5 are Glan-Taylor prisms.

In order to be able to measure the reflected laser spectral characteristic of material, be provided with spectrometer 10 between reflecting mirror 7 and second laser energy detector 9, described spectrometer 10 can detect the spectral characteristic of reflected laser; Device 12 is connected. The spectrometer 10 can input the detected spectral characteristics into the data processor 12 , and the data processor 12 can store and output the corresponding material laser spectral characteristics according to the spectral signal input by the spectrometer 10 . Data processor 12 comprises single-chip microcomputer and industrial computer, and spectrometer 10 and the first laser energy detector 8, the second laser energy detector 9 are connected with industrial computer by single-chip microcomputer, and the curve output by data processor 12 is displayed and output by the display of industrial computer . Laser light source 1, guide rail 2, proportional beam splitter 3, polarizer 4, analyzer 5, sample stage 6, mirror 7, first laser energy detector 8, second laser energy detector 9, spectrometer 10 and detection The electrical and electronic consoles 11 are all located in the same housing, which realizes the integrated setting of the measuring equipment; the front of the housing is provided with an operation hatch, which can be opened to perform operations such as sample placement and replacement, and spectrometer 10 probe installation and disassembly.

The polarizing direction of the polarizer 4 can be set as required, and the light transmission axis of the analyzer 5 can be rotated by 360°. When it is not necessary to measure the polarization characteristics, the transmission axes of the polarizer 4 and the analyzer 5 return to zero; when the polarization characteristics need to be measured, the transmission axes of the polarizer 4 and the analyzer 5 are adjusted to a certain clamp horn. The sample table 6 adopts an insert-type structure. For sheet samples, it can be directly inserted under the tablet for measurement. For block samples, the insert holder is removed and placed directly on the turntable plane for measurement. Among them, the angle between the reflector 7 and the optical axis of the incident laser is 45°, the incident laser passes through the upper edge of the reflector 7, and the reflected laser light of the sample is reflected by the reflector 7 to the THORLABS PM100 second laser energy detector at its lower part. Device 9 or OCEAN OPTICSSPECTRUM HR4000 spectrometer 10. When the optical axis of the second laser energy detector 9 is perpendicular to the sample surface on the sample stage 6, in order to prevent the laser detector 9 from overlapping with the main optical axis of the laser light source 1 and block the incident laser light, the normal direction of the sample surface is approximated at a small angle The measurement principle is to control the angle between the main optical axis of the laser light source 1 and the main optical axis of the laser energy detector to be 3°, measure the reflected laser energy in the normal direction of the sample surface, and the measurement error is not greater than 0.1%. When the data processor 12 includes a single-chip microcomputer and an industrial computer, install a PCI 6221 multifunctional control card in the industrial computer, communicate with the SC101 stepper motor controller through the serial port, drive and guide rail 2, polarizer 4, and polarizer in the housing 5. The corresponding stepping motor movement of the sample stage 6 and the detector electric control turntable 11; the measurement control and data analysis processing program is installed in the industrial computer, which is connected with the display through the VGA interface to perform automatic measurement operation, parameter setting and data analysis. Process analysis.

The measuring principle of basis of the present invention is as follows:

1. Spatial energy distribution measurement of laser reflection field

The laser light reflected by the sample surface is divided into specular reflection and diffuse reflection according to its distribution in space. In diffuse reflection, according to the spatial distribution of light intensity, it can be divided into Mie reflection and Rayleigh reflection. Mie reflection means that when the particle size is greater than 10 times the wavelength, the reflected light intensity has nothing to do with wavelength and angle. Rayleigh reflection means that when the particle size is less than one-tenth of the wavelength, the reflected light intensity is inversely proportional to the fourth power of the wavelength, that is:

It is proportional to the square of the cosine of the included angle φ of the incident direction, that is:

I(φ)＝I ₀ (1+cos ² φ) (2)

The reflected light intensity of the actual material is the superposition of Mie reflection and Rayleigh reflection, and there is no specular reflection. Therefore, the spatial energy distribution of the reflected laser reflection field can be expressed as:

I _s (φ)=I(φ)+I _m ＝I ₀ (1+cos ² φ)+I _m ＝f(φ) (3)

Where: I _m is the Mie reflection field distribution, and is a constant.

The laser energy detector is used to measure the energy distribution of each point in space, so that the reflection law can be judged and the surface characteristics of the material can be obtained.

2. Measurement of laser polarization characteristics

Polarization usually expresses linear polarization, circular polarization or elliptical polarization. The polarization effect produced by ground objects is basically linear polarization, and circular polarization can be completely ignored. There are usually two methods for the mathematical description of polarized light: one is the Jones vector method, and the other is the Stokes (Stokes) parametric method. In the process of target recognition, the Stokes system is generally used to explain the propagation of light in the optical path and the surface of the target. The change in polarization state that occurs upon reflection. The Stokes parameter method uses four mutually independent parameters I, Q, U, and V to fully describe the polarization state of a beam of light. I represents the total intensity of the light wave, so it is always positive; Q represents the intensity difference between the linearly polarized light in the X direction and the Y direction. According to whether the X direction is dominant or the Y direction is dominant or the same, the value of Q is positive, negative or zero. ; U represents the intensity difference between the linearly polarized light in the +45° direction and the -45° direction, according to whether the +45° direction is dominant, the -45° direction is dominant or the same, and the value of U is positive, negative or zero; V represents Whether the right-handed or the left-handed circular polarization component is dominant, according to whether the right-handed direction is dominant, the left-handed direction is dominant or the same, the value of V is positive, negative or zero.

I, Q, U, V parameters are defined as:

$\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; I</span>}\\ \mathrm{<span\; class="notranslate">\; Q</span>}\\ \mathrm{<span\; class="notranslate">\; u</span>}\\ \mathrm{<span\; class="notranslate">\; V</span>}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{c}<span\; class="notranslate">\; <</span>{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}}_{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; <</span>{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\\ <span\; class="notranslate">\; <</span>{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}}_{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; <</span>{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\\ \mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; <</span>{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}}_{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ></span>\\ \mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; <</span>{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}}_{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ></span>\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

or:

和δ_x(t)、δ_y(t)分别表示电场在x、y垂直方向上的振幅和相位；<>的含义是求时间平均值。I₀为光波的总强度，I_o＝I_0°+I_90°＝I_+45°+I_-45°＝I_r+I_l，I_0°、I_90°、I_+45°、I_-45°、I_r、I_l分别表示放置在光波传播路径上一理想偏振片在0°、90°、+45°、-45°方向上的线偏振光以及左旋(l)和右旋(r)圆偏振光强。In the formula:

and δ _x (t), δ _y (t) represent the amplitude and phase of the electric field in the vertical direction of x and y respectively; <> means to calculate the time average value. I ₀ is the total intensity of the light wave, I _o ＝I _0° +I _90° ＝I _+45° +I _-45 °＝I _r +I _l , I _0° , I _90° , I _+45° , I _{- 45°} , I _r , and I _l respectively represent the linearly polarized light and the left-handed (l) and right-handed (r ) circularly polarized light intensity.

When the beam interacts with matter, the four Stokes parameters of the reflected beam are linearly related to the four Stokes parameters of the incident beam. Written in matrix form is:

S _out = M·S _in (6)

M is a Miller matrix of order 4×4, which represents the properties and orientation of the substance. If a beam of light passes through a series of devices one after another, we only need to know the properties of the initial beam and the properties of the devices that it passes through. Find the properties of the outgoing beam.

To fully determine the polarization state of a beam of light, three independent data are required to establish a system of equations for I, Q, and U. In the direction where the angle with the X axis is α, the measured light intensity I(α) is:

I(α)＝12(I+Qcos2α+Usin2α) (7)

Since V represents circularly polarized light, it is usually assumed that V=0 in the measurement of linearly polarized light such as lasers, then: as long as the light intensity of linearly polarized components at three different angles is measured, the parameters I, Q, and U can be solved. When α is three different angles of 0°, 45°, and 90°, the following relations hold:

变化得：

change:

According to formula (7), the test data is nonlinearly fitted to obtain the least squares solutions I, Q, U of the Stokes parameters, and the corresponding polarization degree P and polarization azimuth angle θ (in degrees) are respectively:

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; =</span>\frac{\sqrt{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="Q"\; filenames="HDA0000049224160000011.png"\; state="\{\{state\}\}">Q</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; u</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}{\mathrm{<span\; class="notranslate">\; I</span>}}\\ \mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>\frac{\mathrm{<span\; class="notranslate">\; 180</span>}}{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; the\; tan</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; )</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

3. Small-angle approximate measurement of the normal direction of the sample surface

In the measurement of the spatial energy distribution of the laser reflection field, in order to avoid direct measurement of the reflected laser energy in the normal direction of the sample surface, that is, the angle φ=0° with the incident direction, due to the occlusion of the detector when the laser is perpendicular to the sample surface, The present invention uses a small-angle approximation measurement method to solve this problem.

According to the principle of error transmission, the maximum absolute error of I _s (φ) can be obtained from formula (3):

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; |</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; \&phi;</span>}}<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; \&Delta;\&phi;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; \&Delta;\&phi;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

Among them, Δφ represents the accuracy of the angle φ between the reflected laser and the incident laser (determined by the control accuracy of the stepping motor), and f(φ) represents the laser reflection energy intensity function with the angle φ as an independent variable.

Substituting formula (3) into formula (10), the maximum relative error of I _s (φ) can be obtained as follows:

$\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; \&Delta;\&phi;</span>}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="cos"\; filenames="HDA0000049224160000011.png"\; state="\{\{state\}\}">cos</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="sin"\; filenames="HDA0000049224160000011.png"\; state="\{\{state\}\}">sin</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; |</span>}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="cos"\; filenames="HDA0000049224160000011.png"\; state="\{\{state\}\}">cos</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;\&phi;</span>}}{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}<span\; class="notranslate">\; \&ap;</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="sin"\; filenames="HDA0000049224160000011.png"\; state="\{\{state\}\}">sin</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; |</span>}{\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="cos"\; filenames="HDA0000049224160000011.png"\; state="\{\{state\}\}">cos</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;\&phi;</span>}}{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

It can be seen from the calculation that when 2φ≤8°, its radian value is approximately equal to the sine sin 2φ, and the cosine cos 2φ≥0.990, then the formula (11) can be expressed as:

The azimuth angle control accuracy of the stepping motor of the present invention is ±0.02°, requires the relative error δ≤0.001 to be measured, and requires the control angle φ≤3° (radian value≤0.0524). The reflected laser energy is approximately equal.

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="cos"\; filenames="HDA0000049224160000011.png"\; state="\{\{state\}\}">cos</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="cos"\; filenames="HDA0000049224160000011.png"\; state="\{\{state\}\}">cos</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&ap;</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 13</span>}<span\; class="notranslate">\; )</span>$

For this reason, it is determined that when the detector is perpendicular to the sample surface, the angle φ between the incident beam and the reflected beam is selected to be 3°.

The method for measuring the laser performance of materials is divided into three types: the measurement of the angular distribution characteristic of the laser reflected energy of the material, the measurement of the spectral characteristic and the measurement of the polarization characteristic, wherein: the measurement of the angular distribution characteristic of the laser reflected energy of the material has a second laser energy detector 9, a Table 6 rotates in two modes. All measurement operations are controlled by the industrial computer, and the measurement results can generate light source power monitoring curves, light detection power curves and normalized power curves in rectangular coordinates or polar coordinates. The basic process of measurement is: start the measurement device and measurement software, select the measurement mode and initialize parameters, and perform self-inspection. When the laser light source 1 is in a stable state, the angle distribution characteristics of the laser reflected energy of the sample can be measured under the movement mode of the second laser energy detector 9 or the rotation mode of the sample stage 6 . When the second laser energy detector 9 rotates around the sample stage 6 in the motion mode, or the sample stage 6 is in the rotation mode, when the laser light is vertically incident on the sample surface, the main optical axis of the laser light source 1 and the second laser energy detector 9 are controlled. The included angle of the principal optical axis is 3°; while measuring the angular distribution characteristics of the reflected laser energy, the probe of the spectrometer 10 can be placed at the position of the laser energy detector to measure the spectral characteristics of the reflected laser light. The material polarization characteristic measurement mode is that the main optical axis of the laser light source is perpendicular to the sample surface, the included angle between the main optical axis of the laser light source 1 and the main optical axis of the second laser energy detector 9 is 3°, and the emitted laser light passes through the polarizer 4 It is deflected to the set polarizing angle and incident on the sample surface perpendicularly. The analyzer 5 is driven by a stepping motor and rotates along its own optical axis. The reflected laser light passing through the light transmission axis is measured by the first laser energy detector 8. After Fourier inversion, the four Stokes parameters of the laser reflected by the sample are obtained, and the polarization characteristic parameters such as the degree of polarization and the ellipse angle are calculated by performing differential normalization correction with the laser light source power monitoring curve. During the measurement process, the stepper motor rotates to each azimuth angle, stops first and then measures, which can reduce the interference of the electromagnetic interference during the motor rotation process on the measurement signal. There are three measurement functions: material laser reflection energy angular distribution characteristic measurement, spectral characteristic measurement and polarization characteristic measurement; material laser reflection energy angular distribution characteristic measurement has two modes: detector movement and sample stage rotation; all measurement operations are completed by computer control; The measurement results can generate light source power monitoring curves, light detection power curves, and normalized power curves in Cartesian or polar coordinates; the measurement and calculation results of the polarization state are Stokes parameters, polarization degrees, and ellipse angles.

As shown in Figures 1 and 2: when in use, open the operating hatch on the casing, and place the sample on the sample stage 6, which can be set accordingly according to the shape of the test sample. After the sample is placed, select the emission wavelength of the corresponding laser light source 1 according to the characteristics of the sample. When selecting, start the stepping motor that drives the guide rail 2, so that the main optical axis of the corresponding laser transmitter on the guide rail 2 corresponds to the proportional beam splitter 3; at the same time Turn on the stepping motors of the sample stage 6 and the electric control console 11 of the detector. When measuring the angular distribution characteristics of the laser emission energy of the sample material, the polarizer 4 , the analyzer 5 and the spectrometer 10 are not activated. When the laser polarization characteristics of the sample material need to be measured, the polarizer 4 and the analyzer 5 need to be turned on simultaneously; when the spectral characteristics of the sample material need to be measured, the spectrometer 10 needs to be turned on; the second laser energy detector 9 and the spectrometer 10 measure All the data need to be input into the data processor 12, after being processed by the data processor 12 according to the corresponding signal, the display output is performed by the display. During measurement, part of the laser light emitted by the laser light source 1 is split by the proportional beam splitter 3 and then input into the second laser energy detector 9 , and the other part acts on the sample on the sample stage 6 through the polarizer 4 . The sample on the sample stage 6 reflects the laser light from the laser light source 1 into the second laser energy detector 9 through the analyzer 5 and the mirror 7 . The second laser energy detector 9 detects the laser energy of the proportional beam splitter 3 and inputs it into the data processor 12 , and controls the stability of the output power of the laser light source 1 through the data processor 12 . The second laser energy detector 9 detects the laser signal reflected by the mirror 7 and inputs it into the data processor 12. According to the working state of the polarizer 4 and the analyzer 5, the data processor 12 can output the laser reflection energy of the sample material Angle distribution characteristic curve or material laser energy polarization characteristic curve. At the same time, the data processor 12 can output the material spectral characteristic curve according to the material spectral signal input by the spectrometer 10; thus, the reflected energy angular distribution characteristic, polarization characteristic and spectral characteristic of the sample material can be completed, and the research on the characteristic of the sample material can be completed.

The measurement of the angular distribution characteristics of the laser reflected energy of the material has two modes: the movement of the second laser energy detector 9 and the rotation of the sample stage 6 . All measurement operations are completed under the control of the data processor 12, and the measurement results can generate light source power monitoring curves, light detection power curves and normalized power curves in Cartesian coordinates or polar coordinates. During the measurement process, the rotation of the sample stage 6 or the rotation of the second laser energy detector 9 around the sample stage 6 can be controlled as required; when using the sample stage 6 rotation mode, the main optical axis of the laser light source 1 and the first laser energy detector The included angle of the main optical axis of the device 8 is 3°.

Example 1

In this embodiment, the rotation mode of the second laser energy detector 9 around the sample stage 6 is used to measure the angular distribution characteristics of laser reflected energy of the sample material.

The samples to be tested are: 1 standard gray board with a size of 40mm×50mm and a coating thickness of 1.2mm; 1 piece of laser angle deflection photonic crystal (as a reference board) with a size of 40mm×50mm and a thickness of 2.5mm. The stepper motor controller is the Sc101 stepper motor controller produced by Beijing Optical Instrument Factory. The spectrometer is OCEAN OPTICS SPECTRUM HR4000; the laser energy detector is THORLABSPM100.

When working, put in the sample, start the industrial computer; start the stepper motor controller and put it in the communication state. On the front panel of the stepper motor controller, press the "Settings" button, when the stepper motor controller panel displays "Online", press the "Confirm" button, so that the controller is in the communication state with the industrial computer; start the indoor test software Lasertest; turn on the power switch; select the measurement method, laser wavelength, stepping motor rotation step and other initialization parameters; self-test, under the control of the test software, the device automatically completes the reset of the sample turntable; controls the second laser energy detector 9 to automatically reset To 0° azimuth, perform self-calibration; after self-calibration, laser 1 starts, and after 15 minutes of warm-up, the energy detector measures the reflected light intensity. If the fluctuation of reflected light intensity is less than 5%, it is considered that the light source has stabilized and the laser warm-up is completed. , the measurement can be started; for measurement, the laser light source 1 remains stable, and the second laser energy detector 9 is driven by a stepping motor under the control of the program, and the stepping motor stops every time it rotates one step, and the reflection at a certain azimuth angle is continuously measured The light intensity is 1000 times, take the average value and save it, then the stepper motor rotates one more step, then stops, and then measures the reflected light intensity, repeating in turn, from 0° to 180°; draw a curve, save the data; reset the instrument to zero; when When the stepper motor rotates to 180°, the limit switch starts and the measurement stops, and the stepper motor reversely rotates to drive the second laser energy detector 9 to return to the initial azimuth angle of 0°; To repeat the measurement, repeat the above corresponding steps; if you want to replace the laser light source, repeat the above corresponding steps; if you end the measurement, turn off the power switch of the host, stepper motor controller and industrial computer.

As shown in Figures 3 to 6, among them, Figure 4 is the polar coordinate curve diagram of the sample reflection energy distribution, Figure 5 is the polar coordinate curve diagram of the energy detection after the laser light source splits light by 5%, and Figure 6 is the polar coordinate curve diagram of Figure 4 and Figure 5 For the normalized differential curve diagram, FIG. 3 is a representation of FIG. 4 to FIG. 6 using a Cartesian coordinate system. In the Cartesian coordinate system of Fig. 3, the curve of an approximate straight line on the top represents the energy distribution figure detected by the first laser energy detector 8 after the laser light source 1 separates 5% energy under the effect of the proportional beam splitter 3, as shown in Fig. 3 It can be seen that the output power of the laser light source 1 remains stable; the other two curves in FIG. 3 represent the reflection energy distribution curve of the sample material and the calibration curve after the normalization of the reflection energy distribution curve of the sample material and the output power of the laser light source 1. The laser wavelength of the laser light source 1 is 1064nm, the rotation angle of the second laser energy detector 9 ranges from 0° to 180°, and the angular resolution is 1 degree; the angular distribution characteristic curve of the laser reflected energy of the sample material can be obtained more accurately.

Example 2

In this embodiment, the rotation mode of the sample stage 6 is used to measure the angular distribution characteristics of the laser reflection energy of the sample material.

The samples to be tested are: 1 standard gray board with a size of 40mm×50mm and a coating thickness of 1.2mm; 1 piece of laser angle deflection photonic crystal with a size of 40mm×50mm and a thickness of 2.5mm. The stepper motor controller is the Sc101 stepper motor controller produced by Beijing Optical Instrument Factory. The spectrometer is OCEAN OPTICSSPECTRUM HR4000; the laser energy detector is THORLABS PM100.

When working, put in the sample, start the industrial computer; start the stepper motor controller and put it in the communication state. On the front panel of the stepper motor controller, press the "Settings" button, when the stepper motor controller panel displays "Online", press the "Confirm" button, so that the controller is in the communication state with the industrial computer; start the indoor test software Lasertest; turn on the power switch; select the measurement method, laser wavelength, stepping motor rotation step size and other initialization parameters; self-test, under the control of the test software, the device automatically completes the reset of the sample turntable; controls the second laser energy detector 9 to automatically reset Go to a position at an azimuth angle of 3° from the laser light source, so that it meets the condition of small-angle approximate measurement of the normal direction of the sample surface, and perform self-calibration; after self-calibration, laser 1 starts, and after 15 minutes of warm-up, the first laser energy detector 8 Measure the incident light intensity. If the fluctuation of the incident light intensity is less than 5%, it is considered that the light source has stabilized, the laser is warmed up, and the measurement can be started; during the measurement, the laser emitting end 1 remains stable, and the bracket of the sample stage 6 is controlled by the program. The stepping motor is driven to rotate, and the stepping motor stops every time it rotates one step, and continuously measures the reflected light intensity at a certain azimuth angle for 1000 times, takes the average value and saves it, then the stepping motor rotates another step, stops again, and measures the reflection again Light intensity, repeated in turn, has been from 15° to 165°; draw the curve, save the data; reset the instrument to zero, when the stepping motor rotates to 165°, the limit switch starts, indicating that the measurement stops, so the stepping motor reverses Rotate and drive the sample stage 2 to return to the azimuth angle of 15°; after the test is completed, if you want to repeat the measurement under the same laser wavelength condition, repeat the above steps; if you want to replace the laser light source, repeat the above corresponding steps; Stepper motor controller and industrial computer power switch.

As shown in Figures 7 to 10, Figure 8 is a polar coordinate graph of the energy distribution of the sample emission, Figure 9 is a polar coordinate graph of the energy detection after the laser light source splits light by 5%, and Figure 10 is a normalized graph of Figure 8 and Figure 9 Fig. 7 is a schematic diagram representing Fig. 4 to Fig. 6 in a Cartesian coordinate system. In the Cartesian coordinate system of Fig. 7, the curve of an approximate straight line on the top represents the energy distribution figure detected by the first laser energy detector 8 after the laser light source 1 separates 5% energy under the effect of the proportional beam splitter 3, as shown in Fig. 7 It can be seen that the output power of the laser light source 1 remains stable; the other two curves in FIG. 7 represent the reflection energy distribution curve of the sample material and the calibration curve after the normalization of the reflection energy distribution curve of the sample material and the output power of the laser light source 1. The laser wavelength of the laser light source 1 is 1064nm, the rotation angle of the sample stage 6 is 15°-165°, and the angular resolution is 1 degree; the angular distribution characteristic curve of the laser reflection energy of the sample material can be obtained more accurately.

Example 3

In this embodiment, the laser polarization characteristics of the sample material are measured.

The sample to be tested is: 1 piece of standard gray board, the size is 40mm×50mm, and the coating thickness is 1.2mm.

The stepper motor controller is the Sc101 stepper motor controller produced by Beijing Optical Instrument Factory. The spectrometer is OCEAN OPTICS SPECTRUM HR4000; the laser energy detector is THORLABSPM100.

When working, put in the sample, start the industrial computer; start the stepper motor controller and put it in the communication state. On the front panel of the stepper motor controller, press the "Settings" button, when the stepper motor controller panel displays "Online", press the "Confirm" button, so that the controller is in the communication state with the industrial computer; start the indoor test software Lasertest; select the measurement method and initialization parameters such as laser wavelength, polarization angle, stepping motor rotation step length, etc.; self-test, under the control of the test software, the device automatically completes the reset of the sample turntable; controls the second laser energy detector 9 Automatically reset to the position at an angle of 3° to the main optical axis of the laser light source 1, so that it meets the conditions for approximate measurement of small angles in the normal direction of the sample surface, and performs self-calibration; after self-calibration, the laser light source 1 starts and warms up for 15 minutes The first laser energy detector 8 measures the incident light intensity. If the incident light intensity fluctuation is less than 5%, then the light source is considered to be stable, and the laser warm-up is completed, and the measurement can be started; for measurement, the laser light source 1 remains stable, and the emitted laser light passes through the polarizer 4. The light transmission axis is polarized to the set angle. Under the control of the program, the light transmission axis of the analyzer 5 is driven by a stepping motor and rotates along the direction of the optical axis of the polarizer 5 itself. Every time the stepping motor rotates one step, Stop, measure the reflected light intensity at a certain declination angle continuously for 1000 times, take the average value and save it, then the stepper motor rotates one step, stop again, measure the reflected light intensity again, repeat in turn, from 0° to 360°; Draw the curve and save the data; reset the instrument to zero, when the stepper motor returns to 0°, the limit switch starts, indicating that the measurement stops, so the stepper motor stops at 360°; according to the formula (7), the program automatically checks the test data Perform nonlinear fitting to obtain the least squares solutions I, Q, and U of the Stokes parameters: then obtain the degree of polarization P and ellipse angle θ according to formula (9); To repeat the measurement, repeat the above corresponding steps; if you want to replace the laser light source, repeat the above corresponding steps; if you end the measurement, turn off the power switch of the host, stepper motor controller and industrial computer.

As shown in Figures 10 to 14: Figure 11 is the polar coordinate curve of the sample emission energy distribution, Figure 12 is the polar coordinate curve of the energy detection after the laser light source splits light by 5%, and Figure 14 is the normalization of Figure 11 and Figure 12 Fig. 10 is a schematic diagram representing Fig. 4 to Fig. 6 in a Cartesian coordinate system. In the Cartesian coordinate system of Fig. 10, the curve of an approximate straight line on the top represents the energy distribution figure detected by the first laser energy detector 8 after the laser light source 1 separates 5% energy under the effect of the proportional beam splitter 3, as shown in Fig. 10 It can be seen that the output power of the laser light source 1 remains stable; the other two curves in FIG. 10 represent the reflection energy distribution curve of the sample material and the calibration curve after the normalization of the reflection energy distribution curve of the sample material and the output power of the laser light source 1. As shown in the measurement and calculation results of the laser polarization characteristics of the standard gray board, the laser wavelength of the laser light source 1 is 650nm, and the angular resolution is 1 degree. According to the formula (7), the test data is nonlinearly fitted, and the least square solution of the Stokes parameter is obtained as:

I=1.5354; Q=-0.4189; U=-0.1695;

According to formula (9), the degree of polarization P and ellipse angle θ are obtained as:

P=0.2943 θ=11.0114°

According to the formula (7), the test data is nonlinearly fitted, and the least square solution of the Stokes parameter is obtained as:

_Ic = 1.5711; _Qc = -0.4284; _Uc = -0.1751

According to formula (9), the degree of polarization _Pc and ellipse angle _θc are obtained as:

_Pc = 0.2946 θc = 11.1174°

Compared with the existing measurement methods and devices, the beneficial effect of the present invention is that, due to the adoption of an integrated integrated design, the measurement of the angular distribution characteristics, spectral characteristics and polarization characteristics of laser reflected energy can be completed on the same device, and the functions Integration, measurement automation, high control precision, the main technical performances achieved are: spectrum test range: 0.0.405 ~ 1.1μm; laser light source wavelength: 532nm, 650nm, 980nm, 1064nm; spectrum measurement accuracy: ±0.1nm; laser energy Measurement range: 10μW～30mW; energy resolution: 1μW; energy measurement accuracy: 0.5%; azimuth measurement range: sample stage +90°, detector 0°～180°; azimuth measurement accuracy: ±0.02°; polarization state Ellipsometric angle measurement range: 0°～360°; Polarization state ellipsometric angle measurement accuracy: ±0.05°; Polarization state energy dynamic adjustment range: 0.01～1. The laser reflection energy distribution characteristics, laser spectrum characteristics and laser polarization characteristics of the sample material are obtained through the above measurement, and the research on the corresponding characteristics of the sample material can be realized.

Claims (8)

1. A measuring device for laser properties of materials, characterized in that it includes at least one laser light source (1), and a ratio beam splitter (3) is arranged on the main optical axis of the laser light source (1), and the ratio The main transmission optical path of the beam splitter (3) is provided with the main measurement optical path formed by the second laser energy detector (9) and the rotatable sample stage (6) or the second laser energy detector that can rotate around the sample stage (6). The main measurement optical path formed by the device (9) and the sample stage (6); the secondary transmission optical path is provided with a first laser energy detector (8) capable of monitoring the stability of the emission power of the laser light source (1); the sample stage ( 6) There is a reflector (7) on the reflected light path, and the laser light reflected by the material on the sample stage (6) is reflected into the second laser energy detector (9) through the reflector (7), and the first laser energy detector ( 8) The output end of the second laser energy detector (9) is connected to the data processor (12); the data processor (12) detects the laser energy of the laser light source (1) according to the first laser energy detector (8) signal, adjust and control the output power of the laser light source (1), so that the output power of the laser light source (1) remains stable; after the data processor (12) processes the laser energy signal detected by the second laser energy detector (9), Store and output the corresponding angle distribution characteristics of laser reflection energy of the material; a polarizer (4) is provided between the proportional beam splitter (3) and the sample stage (6); a polarizer (4) is provided between the sample stage (6) and the reflector (7) There is an analyzer (5) matched with the polarizer (4); the light beam of the main optical axis of the laser light source (1) passes through the proportional beam splitter (3) and the polarizer (4) and then enters the sample stage (6 ) on the material; the laser light reflected by the material on the sample stage (6) is reflected into the second laser energy detector (9) after passing through the analyzer (5) and mirror (7); the data processor (12 ) process the laser energy signal detected by the second laser energy detector (9), store and output the corresponding material laser polarization characteristics; The spectrometer (10) for detecting the spectral characteristics of reflected laser light, the output end of the spectrometer (10) is connected to the data processor (12), and the data processor (12) processes the spectral characteristic signal input by the spectrometer (10), and stores And output the spectral characteristics of the corresponding material reflected laser. 2. The measuring device for laser properties of materials according to claim 1, characterized in that: the data processor (12) includes a single-chip microcomputer and an industrial computer, and the industrial computer communicates with the first laser energy detector ( 8) Connect with the second laser energy detector (9). 3. The device for measuring laser properties of materials according to claim 1, characterized in that: the laser light source (1) includes four semiconductor pumped laser emitters arranged in parallel, and the laser emitters are installed on on the guide rail (2). 4. The measuring device for laser properties of materials according to claim 1, characterized in that: the laser wavelength output by the laser light source (1) is 532nm, 650nm, 980nm or 1064nm. 5. The measuring device for laser properties of materials according to claim 1, characterized in that: the sample stage (6) is an insert type sample stage. 6. The measuring device for laser properties of materials according to claim 1, characterized in that: said polarizer (4) and analyzer (5) are Glan-Taylor prisms. 7. The measuring device for laser properties of materials according to claim 1, characterized in that: the material of the proportional beam splitter (3) includes quartz, and the proportional beam splitter (3) converts the energy emitted by the laser light source (1) 5% of the light is split into the first laser energy detector (8), and the first laser energy detector (8) inputs the energy detected by the proportional beam splitter (3) into the data processor (12), and the data processing The device (12) controls the output of the laser light source (1) according to the split energy signal detected by the first laser energy detector (8), so as to keep the output power of the laser light source (1) stable. 8. The device for measuring laser properties of materials according to claim 1, characterized in that: the rotation of the sample stage (6) and the second laser energy detector (9) is driven by a stepping motor.

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