This standard specifies the method for measuring the long pulse laser threshold and slope efficiency of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser bars in a standard laser cavity with a wavelength of 1.06um. GB 11297.4-1989 Measurement method for long pulse laser threshold and slope efficiency of neodymium-doped yttrium aluminum garnet laser bars GB11297.4-1989 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for mormal pulse lasing threshold and slope efficiency of Nd :YAG laser rodsUDC 621. 383.032
26-621. 317. 3
GB 11297.4—89
This standard specifies the method for measuring the long pulse laser threshold and slope efficiency of Nd:YAG laser in a standard laser cavity with a wavelength of 1.06um.
1 Terminology
The definitions of terms used in this standard conform to GB 11293 Terminology of Mormal Laser Materials. 2 Measurement principle
Use a single pulse plane-plane standard spectrum resonator to measure the characteristic curve of the input pump energy and output energy of the Nd:YAG laser rod. In rectangular coordinates, draw a characteristic curve with the input energy as the horizontal axis and the output energy as the vertical axis. Then the intercept of the extended line of the straight part of the characteristic curve with the input energy axis (horizontal axis) is the pulse laser threshold of the rod; the slope of the straight part of the characteristic curve is the slope efficiency of the rod. 3 Measurement quantity and measurement equipment
The measurement device used to measure the long pulse laser threshold and slope efficiency of the Nd:YAG laser rod consists of the following components: pulse laser power supply, pulse xenon lamp, optical cavity, dielectric diaphragm with a wavelength of 1.06 μm, energy meter and internal focusing telescope. The optical system is shown in Figure 1. Figure 1
1—Full reflector diaphragm; 2—Collector cavity 3—Pulse lamp + 4—Energy meter + 5—Internal focusing telescope; 6—Laser sample to be measured: 7—Output end half reflector diaphragm 3.1 The pulse power supply adopts LC discharge circuit. The accuracy of the voltage indicating instrument should be better than 1.5 level. 3.1.1 In the small energy pulse circuit, the inductance L is 30±2 tH, the energy storage capacitor C is 30±2 ±F, and the output voltage range is 0~1 000 V. 3.1.2 In the medium energy pulse power supply discharge circuit, the inductance L is 35±2μH; the energy storage capacitor C is 100±5 μF. The auxiliary output voltage range is 0--2 000 V.
3.2 Pulse xenon lamp adopts straight tube shape.
The Ministry of Machinery and Electronics Industry of the People's Republic of China approved it on October 9, 1988 and implemented it on January 1, 1990.
GB 11297.4--89
3.2.1 Low-energy xenon lamp: gas pressure 5.3×10±1.3×10°Pa, inner diameter 3.5, outer diameter $5, lamp pole distance 50mm or 75nmi, and filter with ultraviolet cutoff material.
3.2.2 Medium-energy xenon lamp: gas pressure 5.3×10±1.3×10°Pa, outer diameter 8, inner diameter 6, lamp pole distance 100mm, and filter with ultraviolet cutoff material.
3.3 The focusing wrist adopts a metal cavity.
3.3.110J The geometric dimensions of the small energy focusing cavity are: major semi-axis 10mm, minor semi-axis 8.8mm, eccentricity 0.47, cavity length is 50mm and 75mm, the reflection surface in the cavity is silver-plated, and the maximum allowable value of the reflection surface roughness R is 0.01. 3.3.250" The geometric dimensions of the medium energy focusing cavity are: major semi-axis 17mm, minor semi-axis 15mm, eccentricity 0.47, cavity length 100mm, the reflection surface in the cavity is silver-plated, and the maximum allowable value of the reflection surface roughness R is 0.01. 3.4 Dielectric diaphragm
3.4.1 The central wavelength of the dielectric diaphragm used for small energy measurement is 1.06μm, and the reflectivity of the total reflector should be greater than 99.7%; the reflectivity of the reflector at the output end is 32±2%.
3.4.2 The center wavelength of the dielectric film used for medium energy measurement is 1.06μm, and the reflectivity of the reflector is 99.7%; the reflectivity of the reflector at the output end is 5%±2%
B.5 Energy meter: The accuracy should reach 10%.
8.6 The collimator of the light modulation path uses an internal focusing telescope, and the accuracy should be better than 10μurad. .7 In order to frequently check the stability of the test system, a calibration laser rod is made of Nd:YAG material. Both ends are coated with anti-reflection film, the rod is 676 in diameter, and the side is rolled with 302\ diamond. 4 Measurement steps and calculations
4.1 Before measuring the laser reading and slope efficiency of the Nd:YAG laser sample pulse, calibrate the test system with a standard laser rod with a known characteristic curve. If it is within the allowable error range, the measurement can be carried out. Otherwise, the test system should be checked, re-debugged, and some components should be replaced to make the test system reach the required accuracy and stability. 4.2 Small energy measurement threshold and slope efficiency
4.2.1 The resonant cavity length of the laser used for small energy measurement is 230mm. The reflectivity of the output is 32%±2%. 4.2.2 Use the internal focusing telescope to adjust the dielectric diaphragms at both ends of the resonant cavity to be coaxial and parallel. 4.2.3 Install the laser rod to be measured into the focusing night, and adjust the end face of the rod to be coaxial and parallel to the resonant cavity. 4.2.4 Start to increase the power supply voltage from 500V, measure one point every 50V, and measure point by point until 900V, and record the output energy of each point. Substitute the voltage value into formula (1) to calculate the input energy FEk
Where: energy storage capacitor, F
input voltage, V
4.2.5 Draw the characteristic curve of input energy E (J) and output energy E (mJ>. Extend the straight line part of the characteristic curve to the horizontal axis. The intercept of the intersection is the slope of the rod, and the slope of the straight line of the characteristic curve is the slope efficiency of the rod. See Figure 2. 4.3
GB11297.4—89
Input energy (J)
The resonant cavity of the medium energy test laser is 400mm long and the reflectivity at the output end is 50%±2%. 4.3.1
Use the focusing telescope in the collimator to adjust the two diaphragms of the resonant cavity to be coaxial and parallel. Place the laser rod to be tested into the focusing cavity, use a light shielding sleeve to match the arc length of the laser rod to be tested, and adjust the rod end face to be parallel to the coaxial II of the resonant cavity. 4.3.2
4.3.3 Start to increase the power supply voltage from 800 V, and measure the output energy (E±) at every 100 V until 1 200 V. 4.3.4 The input energy E of the laser is calculated according to formula (2): E
where: inner rod length, light shielding matching correction factor between rod and lamp arc length, energy storage capacitor F, input voltage, V. 4.3.5 Draw the characteristic curve of input energy E, (J) and output energy E density (mJ), and calculate the value and slope efficiency of the measured laser sample. Refer to Figure 2.
5 Measurement accuracy
The error of the value and slope efficiency of the laser rod measured by this method is ±10%. 6
Test report content
61 Operator's name.
6.2 Measurement date,
6.3 Dimensions and serial number of the laser rod under test.
6.4 Standard data.
6.5 Characteristic curve of the laser rod under test.
6.6 Measurement results: threshold value (J), slope efficiency (%). Additional remarks:
This standard was drafted by the 11th Institute of the Ministry of Machinery and Electronics Industry. The main drafter of this standard is Zhang Peihe.
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