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High precision method and device for measuring wave plate phase delay

A phase delay, high-precision technology, applied in the measurement of color/spectral characteristics, etc., can solve the problems of high cost, large volume of high-precision goniometers, and complicated equipment adjustment.

Inactive Publication Date: 2004-11-17
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The measurement accuracy of these two types of methods is generally around 0.5° to 1°, and the adjustment of equipment is more complicated. Especially in the first type of method, many of them need to measure the angle accurately, and the high-precision goniometer is large in size and high in cost.
In addition, many of these methods are only suitable for measuring quarter-wave plates and not for half-wave and full-wave plates

Method used

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  • High precision method and device for measuring wave plate phase delay
  • High precision method and device for measuring wave plate phase delay
  • High precision method and device for measuring wave plate phase delay

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0077] See example 1 Figure 5 .

[0078] The laser reflection mirrors [2] and [4] form a resonant cavity, and the two ends of the gain tube [1] are respectively fixed with an antireflection window [3] and a reflection mirror [4]. The reflector [2] is installed on the piezoelectric ceramic [6], and can be driven by the piezoelectric ceramic [6] to move along the axis of the cavity to change the cavity length and control the laser to work in a dual-mode or triple-mode state. The wave plate [11] is Install on the clamping device【7】. The output of the laser is received by the photodetector [9] after passing through the polarizer [8], and then the spectrum analyzer (or frequency counter) [16] reads the split mode frequency difference Δν and the longitudinal mode interval Δ. Most components of the system are installed on the base [5], and the entire resonant cavity is partly covered in the outer cover [12] to reduce external disturbances.

example 2

[0079] Example 2 see Figure 6 .

[0080] The laser reflector [2] [4] forms a resonant cavity, and the gain tube [1] is placed in the transverse magnetic field formed by the magnet group [13]. Sealed together. The reflector [2] is installed on the piezoelectric ceramic [6], and can be driven by [6] to move along the axis of the cavity, and the wave plate [11] is installed on the clamping device [7]. Piezoelectric ceramics [6] can be used to adjust the cavity length to make the laser work in a dual-mode or triple-mode state. The output of the laser is received by the photodetector [9] after passing through the polarizer [8], and then the split mode frequency difference Δν and the longitudinal mode interval Δ are read out by the spectrum analyzer [16]. The whole resonant cavity is partly covered in the outer cover [12], and [5] is the base.

example 3

[0081] Example 3 see Figure 7 .

[0082]The laser reflector [2] [4] forms a resonant cavity, and the gain tube [1] is placed in the transverse magnetic field formed by the magnet group [13]. Sealed together. The reflector [2] is installed on the piezoelectric ceramic [6], and can be driven by [6] to move along the axis of the cavity, and the wave plate [11] is installed on the clamping device [7]. Piezoelectric ceramics [6] can be used to adjust the cavity length to make the laser work in a three-mode state. The output of the laser is divided into two paths by the beam splitter [14]. The first path passes through the polarizer [81] and then enters the detector [91], and then the frequency difference is read by the frequency meter [161] after passing through the circuit [151]; Two roads enter detector [92] after polarizing plate [82], then display beat frequency by frequency meter [162] after circuit [152]. 【5】【12】are the base and the cover respectively. Among them, the l...

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Abstract

The invention is a method and device for measuring wave plate phase delay with high precision which belongs to laser measurement technology field, the character lies in: it uses semi inner cavity helium-neon laser, the laser is made up of a gain tube and an independent reflecting mirror. The two ends of the gain tube fixes a reflecting mirror and a transparent window piece, the independent reflecting mirror is driven by piezoelectric ceramic. The measured wave plate is inserted in the laser resonance cavity, the laser output mode generate beat frequency through a polarized piece, which is received by the detector, it is transmitted to the spectrum device or the frequency meter to be displayed after processed by circuit, works out the phase delay according the display. It also adds the transverse magnetic field formed by two groups of magnet at the gain tube axial direction, or uses a wave plate or a set of forcing device to measure the phase delay of semi or whole wave plate. It sets five examples of measuring devices.

Description

technical field [0001] A method and device for measuring waveplate phase delay with high precision belong to the technical field of laser measurement. Background technique [0002] There are two main types of wave plate phase delay measurement methods commonly used at present. One is to build a specific optical path and use the characteristics introduced by the wave plate phase delay to obtain its phase delay by measuring the light intensity and polarization state changes caused by the wave plate rotation. The other is to polarize and split the light output from the light source through a wave plate and make it form heterodyne interference for measurement. The measurement accuracy of these two types of methods is generally around 0.5° to 1°, and the adjustment of equipment is more complicated. Especially in the first type of method, many of them need to measure the angle accurately, and the high-precision goniometer is bulky and expensive. In addition, many of these methods...

Claims

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Application Information

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IPC IPC(8): G01N21/27
Inventor 张书练宗晓斌张毅韩艳梅
Owner TSINGHUA UNIV