Method for measuring phase delay devices with different wavelengths by single wavelength light source and system thereof

Abstract

The invention discloses a method for measuring phase delay devices with different wavelengths by a single wavelength light source and a system thereof, which belong to the technical field of optical measurement. A laser light source of the system is spilt into two beams, one beam orderly passes through a polarizer, an optical modulator, a phase retarder to be tested, a phase compensator, an analyzer, and a photodetector, and then a result display unit is used for displaying an output result; and the other beam is output to a laser monochromator. The method comprises the steps of: measuring displacements of the phase compensator corresponding to a group of light sources with different wavelengths respectively first after the establishment of the system; then establishing a fitting curve according to measured data; adding the phase retarder to be tested into a light path, then selecting a laser light source with any wavelength, adjusting the phase compensator, and recording a compensated distance delta L; and finally calculating the phase retardation quantity delta S of the phase retarder to be tested according to the fitting curve and the compensated distance delta L. The method and the system thereof can perform direct measurement on a phase retarder with any central wavelength to be tested, has high measurement accuracy and simple operation, and is easy to commercialize.

Description

technical field [0001] The invention relates to a method and system for measuring phase delay devices of different wavelengths, in particular to a method and system for measuring phase delay devices of different wavelengths by using a single wavelength light source, belonging to the technical field of optical measurement. Background technique [0002] The phase delay is an important parameter of the phase delay device, and its measurement accuracy directly affects the quality of the application system, and with the development of technology and the deepening of research, people put forward higher requirements for the processing and measurement accuracy of the wave plate , for example, the polarization measurement accuracy of the Space Solar Telescope (SST) has been required to reach 10 -4 above. Therefore, improving the measurement accuracy of the phase delay is of great significance for the design and development of high-precision phase delay devices and systems. At prese...

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Problems solved by technology

[0004] 1. When using the beam-splitting differential measurement method, it is necessary to measure the rotation angle of the compensation device when the extreme point appears, and then convert it into related phase information. The measurement error is large, the mechanism is complicated, and the instrument cost is high;

[0005] 2. When the light intensity method is used, such as the beam splitting differential automatic measurement system with wave plate phase delay, the light intensity of the DC dark spot is directly measured without modulation. Since the absolute value of the light intensity is measured, the light source’s The impact of fluctuations and background light has a great impact on the measurement results, and the measurement accuracy is low;

[0007]4. When the modulation method is used for measurement, if the precision measurement system of the above-mentioned wave plate phase delay is added with a rotatable mechanical-optical rotation modulator, the structure is complex and difficult to install and adjust. High requirements and large errors

[0008] 5. The measurement results of most methods are greatly affected by the installation and adjustment errors such as instrument alignment and coaxiality;

[0009]6. Most of the methods are not suitable for multi-wavelength measurement or achromatic wave plate measurement because the basic parameters of the device are related to wavelength

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