Method capable of accurately measuring phase delay quantity of wave plate

Abstract

A method capable of accurately measuring the phase delay quantity of a wave plate belongs to the technical field of parameter measurement of the wave plate. A device comprises a light source, a diaphragm, a polarizer, the wave plate to be detected, a polarization analyzer, a spectrometer and a computer. A uniformization spectrum transmittance T (lambda) curve can be obtained by measuring a first spectrum intensity I1 (lambda) distribution curve and a second spectrum intensity I2 (lambda) distribution curve. The computer is utilized to calculate the phase delay quantity and other a plurality of physical parameters of the wave plate to be detected according to the wave length of the intersection point between a line with the transmittance as a fixed value and the uniformization spectrum transmittance T (lambda) curve. The method is a non-contact nondestructive measurement technique and can acquire the plurality of physical parameters of the absolute phase delay quantity, the effective phase delay quantity, the thickness, the level and the like of the wave plate to be detected in a wide spectrum range. The method is high in measuring accuracy, a measuring device is easy to adjust, requirements for the position of the polarizer, the position of the wave plate to be detect and the position of the polarization analyzer are not strict, and the method is suitable for measuring a non-compound crystalline wave plate.

Description

technical field [0001] The invention relates to wave plate measurement, in particular to a method for accurately measuring wave plate phase delay. Background technique [0002] The wave plate is an important polarizing device, which is widely used in the fields of modern optical precision measurement technology and polarization technology. The phase delay of the wave plate is the most important technical parameter of the wave plate, and its own accuracy will directly affect the measurement accuracy of the entire system. The phase delay of the wave plate is the additional phase difference between two optical vibrations whose vibration directions are perpendicular to each other. According to the size of the additional phase difference generated by the wave plate, the wave plate can be divided into two categories: one is the phase delay δ 0 A wave plate less than 2π is called a zero-order wave plate. The thickness of the zero-order wave plate is too thin, difficult to process...

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Problems solved by technology

The patent number is ZL200510030094.8, and the title of the invention is "Method and Device for Measuring the Thickness of a Birefringent Uniaxial Crystal Wave Plate", which discloses a method for measuring the thickness of a birefringent uniaxial crystal wave plate. The peak wavelength is used to calculate the thickness of the wave plate, but in the actual measurement process, since the rate of change of the curve near the peak wavelength tends to zero, and sometimes there are multiple peaks, it is very difficult to accurately extract the peak wavelength, and the extracted peak wavelength will be There are considerable errors, which will eventually bring large errors to the measurement results; at the same time, this method requires that the polarizer and the polarizer should be parallel or perpendicular to each other during the measurement process, and the fast axis of the wave plate to be measured should be in line with the polarizer. The included angle of the light transmission axis of the sensor is π / 4 or 3π / 4, and there will be adjustment errors in the actual measurement process, which will also affect the final measurement results

The measurement methods proposed by most other literatures can only measure the effective phase delay of the wave plate and cannot measure the absolute phase delay (see literature: [1] Hou Junfeng, Yu Jia, Wang Dongguang, Deng Yuanyong, Zhang Zhiyong, Sun Yingzi, "Self-calibration method Measuring Waveplate Phase Retardation", [China Laser] Vol.39, No.4.2012, pp173)

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