Device for detecting uniformity of optical crystal

Abstract

The utility model discloses a device for detecting the uniformity of an optical crystal. The device comprises an optical panel, and a detection light source, a lens group, a mobile platform and a CCD (Charge Coupled Device) camera which are arranged on the optical panel and are used for emitting detection light, an objective table is fixed on the two-dimensional mobile platform, a temperature control device for placing a detected optical crystal is mounted on the objective table, and the detection light source, the lens group, the detected optical crystal and the CCD camera are arranged along a light path of the detection light; air pipes used for providing clean and dry air are arranged at the two ends, along the light path, of the temperature control device.

Description

TECHNICAL FIELD

[0001] The utility model relates to optical crystal detection device, especially a device for detecting the uniformity of optical crystal. BACKGROUND

[0002] A crystal is a solid in which the constituent particles are arranged in a three-dimensional periodic array. Because the particles are arranged in an orderly manner, a crystal structure is formed. Different crystals have different crystal structures due to the different types of particles and the different directions and spacings of the particles. Cesium lithium borate (CsLiB6O 10 CLBO is a newly emerging crystal material with excellent deep ultraviolet nonlinear properties, has a tetragonal structure, and has a wide spectral range (transmittance range: 175-2750 nm). At the same time, the CLBO crystal has the advantages of large temperature tolerance, large receiving angle, small dispersion angle, and high conversion efficiency. It is currently the nonlinear optical crystal with the best comprehensive performance for outputting high-energy ultraviolet laser, and the output ultraviolet laser has broad application prospects in the fields of wafer detection, micro-lithography technology, ultraviolet radar, and biomedicine. In particular, the output 266 nm deep ultraviolet laser currently has important applications in the field of semiconductor wafer detection. Deep ultraviolet lasers used in wafer detection must have high energy density, good beam quality, stable pointing, and good long-term stability, which requires the CLBO crystal used in the ultraviolet laser to have fewer defects, good uniformity, and consistency. However, there is currently no effective detection method for screening high-quality CLBO crystals. To screen high-quality CLBO crystals, we simulate the process of generating deep ultraviolet laser by CLBO four times frequency, match the output high beam quality laser and long-term stability optical requirements, use a green laser as a light source to pass through the CLBO crystal, analyze the beam spot passing through the CLBO crystal, and compare it with the actual quality of the existing CLBO crystal to determine the detection method for the internal uniformity of the CLBO crystal.

[0003] Chinese patent CN220603296U reports a device for detecting the internal quality of optical crystal blanks. It uses a high-power semiconductor laser to emit a beam through the crystal, and a high-resolution CCD camera to capture the current crystal beam image. During the process, the crystal is moved by a moving mechanism to capture the overall beam image of the crystal blank. Then, the captured beam image is analyzed by an algorithm to determine whether there are optical non-uniform points inside the crystal. However, it has the following problems: there is no protection measure for the tested crystal. SUMMARY

[0004] To solve the above problems, the detection light source used by the application is a green laser, and other solid-state lasers or fiber lasers with different wavelengths, different pulse widths and different frequencies can also be used as the detection light source, not limited to high-power semiconductor lasers; as a preferred embodiment, the solid-state laser or fiber laser has good beam quality and can be focused to a small spot, so that the resolution of the detection is greatly improved. When detecting the crystal sample, the wavelength that is not absorbed by the crystal sample can be selected according to the crystal sample to be detected, and low-power light can be used to irradiate the crystal, so that the crystal detection is not affected by high-power heating and crystal absorption. In addition, the detected crystal is always blown by clean and dry air to prevent the humidity in the air from being too high to cause the crystal to absorb water and become deliquescent or denatured, so as to detect the internal uniformity of the finished product CLBO optical crystal.

[0005] The utility model provides the following technical scheme:

[0006] A device for detecting the uniformity of an optical crystal, comprising an optical panel, a detection light source for emitting detection light, a lens group, a moving platform, and a CCD camera mounted on the optical panel; a stage is fixed on the moving platform, and a temperature control device for placing the optical crystal to be detected is mounted on the stage; the detection light source, the lens group, the optical crystal to be detected, and the CCD camera are arranged along the optical path of the detection light source; the temperature control device is provided with an air pipe for providing clean and dry air at both ends along the optical path.

[0007] Further, the detection light source is a green laser or a red laser.

[0008] Further, the stage only has the freedom of translation in a plane perpendicular to the optical panel.

[0009] Further, the optical crystal to be detected is a CLBO crystal, an LBO crystal, a BBO crystal, a NdYVO4 crystal, or a KTP crystal.

[0010] The utility model has the following beneficial effects:

[0011] (1) Various optical crystals can be detected by replacing the detection light source.

[0012] (2) The clean and dry gas blowing through the air pipe prevents the humidity in the air from being too high to cause the optical crystal to be detected to absorb water and become deliquescent or denatured. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a perspective view of the application;

[0014] Figure 2 It is a side view of the application;

[0015] The optical panel 1, the detection light source 2, the lens group 3, the moving platform 4, the CCD camera 5, the object table 6, the temperature control device 7 and the air pipe 8. DETAILED DESCRIPTION

[0016] In order to further clarify the technical means and effects adopted by the utility model to achieve the predetermined utility model purposes, the specific embodiments, structures, features and effects according to the utility model are described in detail as follows in combination with the drawings and preferred embodiments.

[0017] The device can detect different optical crystals by using different detection light sources, and the clean and dry gas of the air pipe is blown to prevent the detected optical crystal from absorbing water and being deliquescent or denatured due to excessive humidity in the air.

[0018] The device for detecting the uniformity of an optical crystal comprises an optical panel 1, a detection light source 2, a lens group 3, a moving platform 4 and a CCD camera 5 installed on the optical panel 1 for emitting detection light; an object table 6 is fixed on the moving platform 4, and a temperature control device 7 for placing the detected optical crystal is installed on the object table 6; the detection light source 2, the lens group 3, the detected optical crystal and the CCD camera 5 are arranged along the light path of the detection light source 2; and air pipes 8 for providing clean and dry air are arranged at both ends of the temperature control device 7 along the light path.

[0019] In this embodiment, the temperature control device 7 is a crystal temperature control furnace CH005 from Nanjing Kenai.

[0020] In this embodiment, the detection light source 2 is a green laser.

[0021] In this embodiment, the detection light source 2, the lens group 3 and the CCD camera 5 are all adjusted in height by using a pad block, so as to be installed on the optical panel 1.

[0022] The object table 6 only has the freedom of translation in the plane perpendicular to the optical panel 1, and the position of the object table 6 in the direction along the light path is adjusted by the moving platform 4.

[0023] In this embodiment, the detected optical crystal is a CLBO crystal.

[0024] The detection process of the device in this embodiment is as follows:

[0025] (1) Before the CLBO crystal to be detected is placed in the temperature control device 7, the temperature control device 7 is warmed up to 100-200°C and stabilized, and clean dry air is also blown at this time. At this time, the light beam emitted by the light source 2 passes through the lens group 3, then passes through the temperature control device 7 without the CLBO crystal, and then enters the CCD camera 5. The CCD collects the light spot data (spot size, long and short axis axial direction, long and short axis size, spot roundness, etc.) without the CLBO crystal and performs a light beam pointing test for a period of time.

[0026] (2) The light source 2 is turned off, the CLBO crystal to be detected is placed in the temperature control device 7 and then placed on the stage 6, and the temperature control device 7 is adjusted to the temperature stabilized in step (1) and the gas is blown through the gas pipe 8. Then the light source 2 is turned on, the angle of the CLBO crystal is adjusted, the laser beam is made to be perpendicular to the incident and emergent surfaces of the CLBO crystal, and the light spot of the laser beam passing through the CLBO crystal is collected by the CCD. If there is a difference in the light spot profile (spot size, long and short axis axial direction, long and short axis size, spot roundness, etc.) before and after the CLBO crystal is placed, it can be determined that the material uniformity of the internal light beam passing area of the CLBO is relatively poor. If there is little difference in the light spot profile (spot size, long and short axis axial direction, long and short axis size, spot roundness, etc.) before and after the CLBO crystal is placed, the next step test can be performed.

[0027] (3) After it is ensured that there is no difference in the light spot profile before and after the CLBO is placed, the stage 6 is started to move, so that the stage 6 drives the temperature control device 7 with the CLBO crystal to move, so that the laser beam can pass through all the light passing areas of the crystal, and the change of the light spot profile (spot size, long and short axis axial direction, long and short axis size, spot roundness, etc.) of the laser beam passing through the CLBO crystal and the light beam pointing test during the movement of the stage 6 are recorded by the CCD. According to the difference between the recorded light spot profile (spot size, long and short axis axial direction, long and short axis size, spot roundness, etc.) of the laser beam at different light passing points of the CLBO and the light beam pointing test data before the CLBO crystal is placed, the uniformity of the CLBO crystal can be determined. The stage 6 is controlled to move horizontally or vertically at a certain interval to realize the point-by-point and line-by-line scanning of the laser beam in the cross section of the CLBO crystal, and the light spot profile (spot size, long and short axis axial direction, long and short axis size, spot roundness, etc.) and the light beam pointing of the outgoing laser beam at all points are recorded, and a distribution image of different laser parameters in the cross section of the CLBO crystal can be drawn, so as to quantitatively evaluate the uniformity of the crystal.

[0028] In certain embodiments, according to the detected crystal species, solid-state lasers or fiber lasers can also be used, such as high-repetition picosecond green laser to detect CLBO crystal, infrared picosecond fiber laser to detect LBO crystal, green nanosecond solid-state laser to detect BBO crystal, infrared quasi-continuous fiber laser to detect NdYVO4 crystal, and infrared picosecond solid-state laser to detect KTP crystal.

[0029] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make slight changes or modifications to the above disclosed technical content to obtain equivalent embodiments without departing from the technical solution of the present application. Any modification, equivalent change and modification of the above embodiments made according to the technical essence of the present application still belong to the scope of the technical solution of the present application.

Claims

1. A device for detecting the uniformity of an optical crystal, characterized in that, The application relates to a detection device for detecting optical crystal, which comprises an optical panel, a detection light source for emitting detection light, a lens group, a moving platform, a CCD camera and the like which are installed on the optical panel; a carrier is fixed on the moving platform, the carrier is installed with a temperature control device for placing a detected optical crystal, the detection light source, the lens group, the detected optical crystal and the CCD camera are arranged along the light path of the detection light source; and the temperature control device is provided with air pipes for providing clean dry air at both ends along the light path.

2. The apparatus of claim 1, wherein, The detection light source is a green laser or a red laser.

3. The apparatus of claim 1, wherein, The carrier only has a degree of freedom of translation in a plane perpendicular to the optical panel.

4. The apparatus of claim 1, wherein, The detected optical crystal is a CLBO crystal, an LBO crystal, a BBO crystal, a NdYVO4 crystal or a KTP crystal.

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