CN110736726A - Measuring device and measuring method for low-damage threshold defect of large-caliber fused quartz glass - Google Patents

Abstract

A measuring device and method for measuring low-threshold defects of large-diameter fused silica elements. The system identifies low-threshold defects on large-diameter fused silica elements by detecting the fluorescence spectrum of the defects. Compared with the existing commonly used photothermal weak absorption measurement method, the invention can increase the measurement speed of low-threshold defects by tens of thousands of times.

Description

Measuring device and measuring method for low damage threshold defect of large-diameter fused silica glass

technical field

The invention relates to the field of optical element defect measurement, in particular to a measurement device and measurement method for large-diameter fused silica glass with low damage threshold defects.

Background technique

Large-diameter fused silica optical glass is an important cornerstone of optical components in high-power laser devices, and its surface and sub-surface processing quality directly affects and determines the comprehensive performance indicators of high-power laser systems (such as peak power, beam quality, etc.). The current mainstream fused silica processing technology often produces various types of defects on the surface and sub-surface of fused silica glass, among which low damage threshold defects can cause fatal damage to optical components in high-power laser devices, thus seriously restricting the The performance of the laser system is improved, so the accurate measurement of low-threshold defects on the surface of large-diameter fused silica is of great significance.

The existing common method for detecting low-threshold defects on the surface of small-diameter fused silica glass is photothermal weak absorption measurement. Such as 400×400mm), if the measurement method is two-dimensional point-by-point scanning, the photothermal weak absorption measurement method needs about 50,000 hours to complete the measurement of low-threshold defects in the full aperture of large-diameter fused silica glass, which is obviously inappropriate. actual. In view of this, the large-diameter fused silica components currently produced often do not have the process of defect detection, so there are many potential safety hazards in strong laser devices.

SUMMARY OF THE INVENTION

In order to solve the shortcoming of the low-threshold defect measurement speed of the existing method, the present invention provides a measurement device and a measurement method for the low-threshold defect of a large-diameter fused silica element, which can increase the measurement speed of the existing low-threshold defect by tens of thousands times.

The technical solution of the present invention is as follows:

A low-threshold defect measurement device for large-diameter fused silica glass, which is characterized in that it includes a two-dimensional mechanical scanning mechanism, a laser light source, an optical filter, a spectrometer, a stepping motor controller, a data collector, a laser controller and a computer. The two-dimensional mechanical scanning mechanism is used to place the large-diameter fused silica glass to be measured, and the laser light emitted by the laser light source is irradiated on the surface of the large-diameter fused silica glass to be measured. The direction of the fluorescence emitted by the surface defects of the large-diameter fused silica glass is the filter and the spectrometer in sequence, the output end of the spectrometer is connected with the input end of the computer, and the output end of the computer is respectively The stepping motor controller is connected with the control end of the two-dimensional mechanical scanning mechanism, and is connected with the control end of the laser light source through the laser controller.

The laser is used to provide the excitation light source for the measurement system, and the spectrometer is used to detect the fluorescence spectrum of low-threshold defects (through previous experimental studies, we found that on the surface of fused silica glass, almost all low-threshold defects have fluorescence at specific wavelength positions) Therefore, by measuring the fluorescence spectrum, it can be judged in turn whether there are low-threshold defects on the surface of the fused silica sample), the filter is used to filter out ambient stray light of other wavelengths, and the two-dimensional scanning mechanism is used to scan in two dimensions. The large-diameter fused silica glass is measured, the stepping motor controller is used to control the mechanical movement of the two-dimensional scanning mechanism, the laser controller is used to control the laser, the data collector is used to collect the electrical signals output by the detector, and the computer is used to realize hardware control, data Automatic measurement and control functions such as acquisition and data storage.

Using the above-mentioned measuring device for low-threshold defects of large-diameter fused silica glass, the main measurement steps are as follows:

1) The large-diameter fused silica glass to be measured is placed on the two-dimensional mechanical scanning mechanism, and the laser output from the laser light source is irradiated on the surface of the large-diameter fused silica glass to be measured. The spectrometer and the filter are aligned with the fluorescence emitted by the surface defects of the large-diameter fused silica glass to be tested;

2) Start the computer, under the control of the computer, the stepping motor controller controls the two-dimensional mechanical scanning mechanism, and moves the large-diameter fused silica glass to be measured to the starting point. position, the laser output from the laser light source is irradiated on the starting position of the surface of the large-diameter fused silica glass to be measured, and let this position be n=1, the position of the laser scanning irradiation of the large-diameter fused silica glass to be measured A total of N;

3) Under the control of the computer, the laser light output from the laser light source 3 is irradiated at the position n on the surface of the large-diameter fused silica glass to be measured, and the spectrometer measures the large-diameter fused silica glass to be measured. the fluorescence spectrum emitted at the surface position n and input to the computer;

4) The computer judges whether there is a fluorescence spectrum corresponding to a low-threshold defect at the position n, if there is a fluorescence spectrum, it means that the position has a low-threshold defect, and the computer records the coordinates of the position n;

5) The computer controls the two-dimensional mechanical scanning mechanism 1 through the stepping motor controller, moves the large-diameter fused silica glass to be measured to the position n+1, and sets n=n+1 , when n≤N, go back to step 3); when n>N, go to the next step;

6) The computer outputs the coordinates of all low-threshold defects, that is, the measurement and coordinate positioning of the low-threshold defects of large-diameter fused silica glass are realized within the full-diameter range, and the measurement ends.

The advantages of the present invention are as follows:

Compared with the existing photothermal weak absorption measurement method (the size of the single measurement area is about 10×10 μm), the single measurement area of the present invention can reach 5×5 mm, so the measurement speed can be increased by tens of thousands of times.

Description of drawings

FIG. 1 is a schematic structural diagram of a measuring device for low-threshold defects of large-diameter fused silica glass.

FIG. 2 is a schematic diagram of a two-dimensional laser scanning trajectory.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and embodiments, but the protection scope of the present invention should not be limited by this.

Example 1:

Please refer to FIG. 1 first. FIG. 1 is a schematic structural diagram of a device for measuring low-threshold defects of large-diameter fused silica glass according to the present invention. As can be seen from the figure, the measuring device for the low-threshold defect of large-diameter fused silica glass according to the present invention is characterized in that it includes a two-dimensional mechanical scanning mechanism 1, a laser light source 3, an optical filter 4, a spectrometer 5, a stepping motor controller 6, a data acquisition device 7, laser controller 8 and computer 9, the two-dimensional mechanical scanning mechanism 1 is used to place the large-diameter fused silica glass 2 to be measured, and the laser light emitted by the laser light source 3 is irradiated on the to-be-measured On the surface of the large-diameter fused silica glass 2, the direction of fluorescence emitted by the surface defects of the large-diameter fused silica glass 2 to be measured is followed by the filter 4 and the spectrometer 5. The output end of the spectrometer 5 is connected to the The input end of the computer 9 is connected, and the output end of the computer 9 is connected to the control end of the two-dimensional mechanical scanning mechanism 1 through the stepping motor controller 6, and the laser control The device 8 is connected to the control end of the laser light source 3 .

The laser light emitted by the laser light source 3 is irradiated on the surface of the large-diameter fused silica glass 2 to be tested, and the fluorescence emitted by the defects on the surface of the large-diameter fused silica glass 2 to be tested passes through the filter 4. collected by spectrometer 5.

The laser controller 8 is used to control the laser light source 3 .

The data collector 7 is used to collect the signal output by the spectrometer 5 .

The stepping motor controller 6 controls the two-dimensional mechanical scanning mechanism 1 .

The working process of this measuring device is as follows:

1) placing the large-diameter fused silica glass 2 to be measured on the two-dimensional mechanical scanning mechanism 1, and the laser output from the laser light source 3 is irradiated on the surface of the large-diameter fused silica glass 2 to be measured, Adjust the spectrometer 5 and the filter 4 to align the fluorescence emitted by the surface defects of the large-diameter fused silica glass 2 to be measured;

2) Start the computer 9, under the control of the computer 9, the stepping motor controller 6 controls the two-dimensional mechanical scanning mechanism 1, and the large-diameter fused silica glass to be measured is 2 Move to the starting position, the laser output from the laser light source 3 is irradiated on the starting position of the surface of the large-diameter fused silica glass 2 to be measured, and this position is n=1, and the large-diameter fused silica glass to be measured is Quartz glass 2 has a total of N positions for laser scanning irradiation;

3) Under the control of the computer 9, the laser light output from the laser light source 3 is irradiated at the position n on the surface of the large-diameter fused silica glass 2 to be measured, and the spectrometer 5 measures the large-diameter to be measured. The fluorescence spectrum emitted by the surface position n of the fused silica glass 2 is input into the computer 9;

4) The computer 9 judges whether there is a fluorescence spectrum corresponding to the low-threshold defect at the position n, if there is a fluorescence spectrum, it means that the position has a low-threshold defect, and the computer 9 records the coordinates of the position n;

5) The computer 9 controls the two-dimensional mechanical scanning mechanism 1 through the stepping motor controller 6, moves the large-diameter fused silica glass 2 to be measured to the position n+1, and makes n= n+1, when n≤N, go back to step 3); when n>N, go to the next step;

6) The computer 9 outputs the coordinates of all low-threshold defects, that is, the measurement and coordinate positioning of the low-threshold defects of large-diameter fused silica glass are realized within the full-diameter range, and the measurement ends.

Experiments show that the invention can increase the measurement speed of low-threshold defects by tens of thousands of times.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above-mentioned specific embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principle of the present invention, any modifications, equivalent replacements, improvements, etc. made should be included within the protection scope of the present invention.

Claims (2)

1. The measuring device for the low threshold defect of large-caliber fused silica glass is characterized by comprising a two-dimensional mechanical scanning mechanism (1), a laser light source (3), a light filter (4), a spectrometer (5), a stepping motor controller (6), a data acquisition unit (7), a laser controller (8) and a computer (9), wherein the two-dimensional mechanical scanning mechanism (1) is used for placing the large-caliber fused silica glass (2) to be measured, laser emitted by the laser light source (3) irradiates on the surface of the large-caliber fused silica glass (2) to be measured, the fluorescence direction emitted by the surface defect of the large-caliber fused silica glass (2) to be measured is sequentially the light filter (4) and the spectrometer (5), the output end of the spectrometer (5) is connected with the input end of the computer (9), and the output end of the computer (9) is respectively connected with the control end of the two-dimensional mechanical scanning mechanism (1) through the stepping motor controller (6), and the laser controller (8) is connected with the control end of the laser light source (3).
2. 2. The method for measuring the large-caliber fused silica glass low-threshold defect by using the measuring device of the large-caliber fused silica glass low-threshold defect as claimed in claim 1, characterized by comprising the following steps:

   1) placing the large-caliber fused quartz glass (2) to be detected on the two-dimensional mechanical scanning mechanism (1), irradiating the laser output by the laser source (3) on the surface of the large-caliber fused quartz glass (2) to be detected, and adjusting the spectrometer (5) and the optical filter (4) to align to the fluorescence emitted by the surface defect of the large-caliber fused quartz glass (2) to be detected;

   2) starting the computer (9), wherein under the control of the computer (9), the stepping motor controller (6) controls the two-dimensional mechanical scanning mechanism (1) to move the large-caliber fused quartz glass (2) to be detected to an initial position, laser output by the laser source (3) irradiates the initial position on the surface of the large-caliber fused quartz glass (2) to be detected, the position is N-1, and the number of positions irradiated by the large-caliber fused quartz glass (2) to be detected in a laser scanning mode is N;

   3) under the control of the computer (9), the laser output by the laser source (3) irradiates the position n on the surface of the large-caliber fused quartz glass (2) to be measured, and the spectrometer (5) measures the fluorescence spectrum emitted by the position n on the surface of the large-caliber fused quartz glass (2) to be measured and inputs the fluorescence spectrum into the computer (9);

   4) the computer (9) judges whether the position n has a fluorescence spectrum corresponding to the low threshold defect, if so, the computer (9) records the coordinate of the position n, namely the position has the low threshold defect;

   5) the computer (9) controls the two-dimensional mechanical scanning mechanism (1) through the stepping motor controller (6), moves the large-caliber fused quartz glass (2) to be detected to a position N +1, and enables N to be N +1, and when N is less than or equal to N, the step returns to the step 3), and when N is greater than N, the step goes to the step ;

   6) and the computer (9) outputs the coordinates of all the low-threshold defects, namely the measurement and the coordinate positioning of the large-caliber fused quartz glass low-threshold defects are realized in the full-caliber range, and the measurement is finished.

Images