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Laser self-mixing grating interferometer and its measuring method

A grating interference and self-mixing technology, which is applied in the direction of measuring devices, instruments, and optical devices, can solve the problems of complex structure and difficult adjustment of optical path, and achieve the effect of large measurement range, strong anti-interference and simple structure

Inactive Publication Date: 2017-10-10
NANJING NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the optical path of the existing grating interferometer contains multiple photodetectors, polarization beam splitters, wave plates and other components, the structure is complex, and the optical path adjustment is difficult

Method used

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  • Laser self-mixing grating interferometer and its measuring method
  • Laser self-mixing grating interferometer and its measuring method
  • Laser self-mixing grating interferometer and its measuring method

Examples

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Effect test

Embodiment 1

[0028] Such as figure 1 , The laser self-mixing grating interferometer in this embodiment includes: a laser 1, a transmission diffraction grating 21, a plane mirror 3, a photodetector 4, an electrical signal processing system 5, and a data acquisition and analysis system 6. The light output by the laser 1 is vertically incident on the transmissive diffraction grating 21 , and each level is symmetrically distributed on both sides of the incident light path. The plane reflector 3 is placed on the first-order diffraction optical path, and the plane reflector 3 is adjusted so that the first-order diffracted light beam is vertically incident on the plane reflector and returns along the original optical path, and then enters the diffraction grating 21 again, and secondary diffraction occurs. The first-order diffracted light returns to the cavity of the laser along the opposite direction of the output light of the laser 1, and self-mixes and interferes with the light in the cavity to...

Embodiment 2

[0030] Such as image 3 , The laser self-mixing grating interferometer in this embodiment includes: a laser 1, a transmission diffraction grating 21, a plane mirror 3, a photodetector 4, an electrical signal processing system 5, and a data acquisition and analysis system 6. The light output by the laser 1 is vertically incident on the transmissive diffraction grating 21 , and each level is symmetrically distributed on both sides of the incident light path. The plane reflector 3 is placed on the second-order diffraction light path, and the plane reflector 3 is adjusted so that the second-order diffracted light is vertically incident on the plane reflector and returns along the original optical path, and then enters the diffraction grating 21 again, and secondary diffraction occurs. The second-order diffracted light returns to the cavity of the laser along the opposite direction of the output light of the laser 1, and self-mixes and interferes with the light in the cavity to mod...

Embodiment 3

[0032] Such as Figure 4 , The laser self-mixing grating interferometer in this embodiment includes: a laser 1, a reflective diffraction grating 22, a plane mirror 3, a photodetector 4, an electrical signal processing system 5, and a data acquisition and analysis system 6. The light output by the laser 1 is vertically incident on the reflective diffraction grating 21, and the 0th-order diffracted light returns to the resonator of the laser 1 along the original optical path, and the remaining levels are symmetrically distributed on both sides of the incident optical path. The plane reflector 3 is placed on the first-order diffraction optical path, and the plane reflector 3 is adjusted so that the first-order diffracted light is vertically incident on the plane reflector and returns along the original optical path, and then enters the diffraction grating 22 again, and secondary diffraction occurs. The first-order diffracted light returns to the cavity of the laser along the oppo...

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Abstract

The invention discloses a laser self-mixing grating interferometer and a measuring method thereof. The interferometer includes a laser, a diffraction grating, a plane mirror, a photoelectric detector, an electrical signal processing system, and a data acquisition and analysis system; the diffraction grating is placed on the output optical path of the laser, and its displacement direction is perpendicular to the output optical path of the laser; The laser beam is vertically incident on the diffraction grating, and various levels of diffracted light are symmetrically distributed on both sides of the incident light path. The plane reflector is set on the optical path of a certain m-order diffracted light, so that the mth (m≠0) order diffracted light is incident vertically. It returns to the plane mirror and returns along the original optical path, and then enters the diffraction grating again for secondary diffraction. The secondary diffracted light carries the grating displacement information and returns to the laser cavity along the opposite direction of the laser output light to generate self-mixing interference with the light in the cavity. The invention has the advantages of simple and compact structure, low cost, strong anti-interference ability, no need to control optical feedback level, automatic recognition of displacement direction and the like.

Description

technical field [0001] The invention belongs to the technical field of precision displacement measurement, and in particular relates to a laser self-mixing grating interferometer for measuring tiny displacements and a measurement method thereof. Background technique [0002] Laser interferometer is based on the method of optical interference, using the wavelength of light as the measuring ruler. It is an important tool for precision displacement measurement in the fields of science, engineering and industry. However, many interferometers on the market are complex and costly, and are large and expensive instruments. For example, the 5529A dual-frequency interferometer of Agilent Company of the United States. Laser self-mixing interference technology is a new type of interferometry technology with high application value that has emerged in recent years. This technology uses part of the laser light reflected or scattered by the measured object to recouple into the laser resonat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01B9/02G01B11/02
Inventor 郭冬梅王鸣郝辉夏巍倪小琦
Owner NANJING NORMAL UNIVERSITY
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