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High-precision frequency conversion interference four-step phase-shift calibration method

A four-step phase shift and calibration method technology, which is applied in the field of four-step phase shift calibration of high-precision frequency conversion interference, can solve the problem of low precision and achieve the effect of precise calibration and high calibration accuracy

Active Publication Date: 2015-01-28
XIAN TECHNOLOGICAL UNIV
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Problems solved by technology

[0005] The purpose of the present invention is to provide a four-step phase-shift calibration method of high-precision frequency conversion interference to solve the problem of low precision when calibration based on a single sampling point

Method used

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  • High-precision frequency conversion interference four-step phase-shift calibration method
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  • High-precision frequency conversion interference four-step phase-shift calibration method

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Embodiment

[0019] In variable frequency phase shift interferometry, when the test wavelength is When , the light intensity value of a sampling point in the interference field can be written as follows:

[0020] (1)

[0021] In the formula, is the background light intensity, is the modulation intensity, is the length of the interference cavity.

[0022] When the test wavelength is When , the light intensity value of a sampling point in the interference field can be written as follows:

[0023] (2)

[0024] In the formula, , is the number of phase shift steps, which is also the number of frequency conversions, is the wavelength step.

[0025] The above formula can be transformed into

[0026]

[0027] (3)

[0028] In four-step phase-shift interferometry, let , the above formula can be simplified as

[0029] (4)

[0030] During the phase shift, if the first phase shift error , then the light intensity of the interference field can be...

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Abstract

The invention relates to a high-precision frequency conversion interference four-step phase-shift calibration method. According to the common phase frequency conversion phase-shifting calibrating method, the following defects exist: the random error is large; only single sampling point is analyzed, so that the influence of the random error can not be eliminated easily; and comprehensiveness deficiency exists and calibration situations of all sampling points can not be reflected comprehensively during measurement, so that the calibration precision is low. The provide method has the following steps: constructing a Fizeau interference test light path, collecting an original interferogram of reference light and test light and storing the original interferogram into a computer; adjusting a drive voltage of a frequency conversion laser, changing an output wavelength value, collecting an error interferogram, and storing the error interferogram into the computer; and realizing precise calibration of a phase. With the method, the precise calibration of the phase can be realized; the influence on the calibration by the random error can be eliminated.

Description

technical field [0001] The invention belongs to the technical field of optical detection, and in particular relates to a four-step phase shift calibration method of high-precision frequency conversion interference. Background technique [0002] Phase shift interferometry technology is one of the important means of optical surface profile detection. Generally, phase shifting methods can be divided into two categories: hardware phase shifting and variable frequency phase shifting. Hardware phase-shift interference generally uses methods such as pushing piezoelectric ceramics (PZT), rotating polarizing devices (wave plates, polarizers), moving diffraction gratings or tilting plates to achieve phase modulation. Among them, pushing piezoelectric ceramics (PZT) to generate phase shift is the most widely used. Frequency-variable phase-shift interference achieves phase modulation by changing the frequency of the light source, and the light source uses a wavelength-tunable laser. ...

Claims

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Application Information

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IPC IPC(8): G01J9/02G01B11/24
Inventor 田爱玲马迪刘剑刘丙才王红军
Owner XIAN TECHNOLOGICAL UNIV
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