This standard specifies the measurement and calculation method for measuring the side scattered light intensity generated by the uneven refraction and scattering particles in the laser rod when the light wave with a wavelength of 632.8nm passes through the laser rod. GB 11297.2-1989 Measurement method of side scattering coefficient of laser rod GB11297.2-1989 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for side direction scatlering coefficient of laser rods
UDC621.383.032
26:574.43
GB 11297. 2—89
This standard specifies the measurement and calculation method for the side scattered light intensity generated when a light wave with a wavelength of 632.8 ntl passes through a laser rod and encounters the uneven refractive index and scattering particles in the rod. Terminology
The definitions of the terms used in this standard are in accordance with GB11293 "Terms of Solid Laser Materials". 2 Measurement Principle
Due to the uneven refractive index of the micro-regions in the light rod and the existence of scattering particles, the light is side-scattered. The energy of these side-scattered rays is collected by an integrating sphere and measured as side-scattering measurement. When light propagates in a transparent medium, it obeys the Bouguer exponential attenuation law: I = Ioe-at.
Where: 1 — transmitted light intensity, mW;
I- incident light intensity, mW,
-- light loss coefficient.%*cm-1;
L-the length of the medium through which the light passes.cm.
When the medium is uniform, its loss coefficient α can be regarded as due to absorption, which is the absorption coefficient: Ln
I,(1 - p)3
Where: P—reflection coefficient of the end face of a medium; I.—transmitted light intensity, mW.
When light passes through a laser body with scattering particles, there is not only absorption but also strong scattered light, and its loss coefficient is the sum of the absorbed light and scattered light:
=+
From formula (3), it can be seen that in a laser rod with absorption and scattering, it is impossible to accurately measure the absorption and scattering coefficients at the same time. For this reason, the scattered light intensity I is added to the transmitted light intensity I, and both are treated as transmitted light. The transmitted light intensity I is introduced as +
. According to the Bouguer's law, the scattered light intensity coefficient formula is derived: -h=
Iinl1-号
（4）
Substituting the measured scattered light intensity I and light intensity I into formula (5), the side scattering coefficient coefficient of the measured laser can be calculated. The unit is %-cm-
Approved by the Ministry of Machinery and Electronics Industry of the People's Republic of China on October 9, 1988 and implemented on January 1, 1990
3 Measurement device and measurement conditions
GB11297.2-89
The laser rod side scattering coefficient measurement device consists of the following components and instruments: a cyanamide laser light source with a wavelength of 632.8nm, a beam expansion collimator, an adjustable light bar, a laser rod fixture bracket, an integrating sphere, a reflected light cone, a photoelectric receiving element and a display instrument. Its optical system is shown in Figure 1:
1-Ammonia laser light source 12-Band expansion collimator; 3-Light bar; 4-Measured laser rod; 5-Integrating sphere $6-Photoelectric receiving element, 7-Display instrument +8-Reflected light chain 3.1 The power fluctuation of the nitrogen amide laser light source should be less than 1.0%. 3. 2 The divergence of the light source after beam expansion should be less than 3mrad. The inner diameter of the integrating sphere is 200, and the inner wall is coated with matte paint or magnesium oxide reflective coating. The opening rate of the integrating sphere is 1.2%. It is measured at 90°. 3.3
3.4 ​​The photoelectric receiving element uses 2CR101 silicon photocell or other photoelectric receiving elements. 3.5
The display instrument uses a digital voltmeter with an accuracy better than 1.0% or other instruments with equivalent accuracy. The reflected light cone can be made of polyvinyl fluoride or porcelain material into a 30° angle. When measuring, the light beam must be aligned with the part of the light cone. The measurement should be carried out in a dark room.
4 Measurement steps
Turn on the atmospheric laser light source and preheat for 15~30min. 4.2 After the light source is stable, do not place the laser rod to be measured, and measure the scattering coefficient in the integrating sphere to calibrate the stability of the measurement system. The general lasing coefficient of air is 0.01%-cm-1. If the measurement system does not reach this order of magnitude, the system must be re-debugged to avoid errors. 4.3 Place the laser rod to be tested on the fixture first, and adjust the aperture of the light bar so that the diameter of the light source beam is equal to 90% of the diameter of the laser rod to be tested. Then push the integrating sphere so that the laser rod to be tested is in the middle part of the sphere, and adjust it so that the axis of the laser sample to be tested, the beam and the center of the opening of the integrating sphere are coaxial. Note: The laser rod to be tested is placed on the fixture, and no stress is allowed to exist, otherwise the test results will be lost. 4.4 Insert the reflected light cone into the light outlet of the integrating sphere. Measure the light intensity 1. 4.5 Remove the reflected light cone and measure the light intensity J. Use light absorbing materials to remove the transmitted light at a distance, and do not allow any light to be reflected back into the integrating sphere.
4.6 Push the laser rod out of the integrating sphere so that the front end of the rod is at the entrance of the integrating sphere, and measure the forward scattered light intensity 12. 4.7 The side scattered light intensity I of the laser rod:
I=I-I
4.8 Substitute the light intensity 7 and the scattered light intensity I into formula (5) to calculate the side scattering coefficient of the measured laser rod -h. (6)
5 Measurement accuracy
The test error of this standard method is ±5%. Test report content
6.1 Operator's name
6.2 Measurement date.
6.3 The number and size of the measured light rod.
6.4 Total light intensity 1.
6. 5 Side scattered light intensity Ih
6.6 Calculate the side scattering coefficient h.
Additional Notes:
GB 11297. 2--89bzxz.net
This standard was drafted by the 11th Research Institute of the Ministry of Machinery and Electronics Industry. The main drafter of this standard is Zhang Peihe.
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