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Self-mixed intervention Doppler velometer based on two-frequency laser

A technology of Doppler velocimeter and dual-frequency laser, which is applied to devices, instruments, and measuring devices using optical methods, and can solve the problem of low cost performance

Inactive Publication Date: 2005-03-16
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The frequency shifter of this device uses expensive acousto-optic modulation devices, which makes the system not cost-effective

Method used

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  • Self-mixed intervention Doppler velometer based on two-frequency laser
  • Self-mixed intervention Doppler velometer based on two-frequency laser
  • Self-mixed intervention Doppler velometer based on two-frequency laser

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Embodiment Construction

[0035] The experimental device of the present invention is as figure 1 As shown, 1 is the tail light output mirror of the HeNe laser, and its reflectivity is generally 99.8%. 2 is the gain tube of the laser, which is filled with a mixed gas of HeNe. Beam output mirror, the reflectivity is generally 98%. 1, 2, 3 and 4 together form the main body of a HeNe laser. Since the light source used in the present invention is a dual-frequency laser, a stress is applied to the existing laser window through the mechanical stress applying device 5 to generate a birefringence effect. The mechanical stress applying device is a reinforcing ring inlaid with a screw, and the tension of the screw can be adjusted to adjust the size of the stress. At the same time, a transverse magnetic field generator 6 is placed on both sides of the laser gain tube, which is composed of two permanent magnets. The direction of the transverse magnetic field generated by the transverse magnetic field generator ...

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Abstract

It is a Doppler velocimeter based on self-mixed intervention effect and belongs to laser measurement field, which comprises light source, measurement part and signal process three parts. The system light source uses double-frequency laser and locates a quarter of wave sheet in the system measurement part, that is system outer chamber, wherein, the light beam moves around in the outer chamber for once and makes the polarization direction turned into the original vertical direction. As to the velocimeter, when there is no Doppler frequency shift, the laser power spectrum has only one spectrum line; when there exists Doppler frequency shift, the power spectrum has two original spectrum lines and the differential value between the two spectrum lines relative beat frequency signals represents the velocity direction and the distance between the two spectrum lines is converted into velocity.

Description

technical field [0001] A self-mixing interference Doppler velocimeter based on a dual-frequency laser belongs to the technical field of laser velocimetry. Background technique [0002] Laser Doppler velocimetry technology is widely used. Doppler velocimetry based on interference effect mainly includes traditional Michelson interference Doppler velocimetry and self-mixing interference Doppler velocimetry. The optical path of the traditional Michelson interferometric Doppler velocimeter is relatively complex, and requires high collimation of the system. Self-hybrid interference Doppler velocimetry is a new velocity measurement method that has emerged since the 1980s. The optical path system of this speed measuring device has only one laser and one reflector. The light output from the laser is Doppler shifted to form a beat frequency with the light in the cavity, and the velocity information can be obtained by analyzing the beat frequency signal. The self-mixing interferomet...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01P3/36G01S17/58
Inventor 刘刚张书练朱钧李岩
Owner TSINGHUA UNIV
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