Acta Photonica Sinica, Volume. 52, Issue 5, 0552215(2023)
High-precision Measurement Methods Research of Phase Retardance of Waveplates at 0°~360°
To measure the phase retardance and the fast-axis position angel of non-achromatic waveplates accurately, a high-precision measurement system is established based on the fitting light intensity method and spectral analysis method, which can realize the high-precision measurement of the retardance of non-achromatic waveplates at 0°~360°. The measuring system is composed of a white light source, an aperture diaphragm, a narrow band filter, a Glan Taylor prism as polarization generator, a non-achromatic waveplate to be measured, a Glan Taylor prism as polarization analyzer, an optical power meter or spectrometer. When the phase retardance and the fast-axis position angel of non-achromatic waveplates are measured by the fitting light intensity method, the white light emitted by the white light source is collimated parallel by the collimating system, then it passes through an aperture diaphragm, a narrow filter and a polarization generator, which is modulated into monochromatic linearly polarized light. Next the linearly polarized light goes through the waveplates and the polarization analyzer, is finally received by the optical power meter. During the whole measuring process, the high precision motor drives non-achromatic waveplates that are to be measured to rotate uniformly. However, in the measurement process of spectral analysis measuring method, it is necessary to move the narrow filter out of the optical measurement path, and replace the power meter with the spectrometer as the terminal detection device, in this case, non-achromatic waveplates are not needed to rotate by the motor. Before the formal measurement of the retardance and the initial fast-axis position angle of waveplates, the stability of the measurement system and the sources of measurement errors are analyzed in detail in this paper. Under the light intensity measurement method, the influence of random errors such as light source intensity jetter, the initial fast-axis position angle and the rotating position angle of the rotating waveplate and some system errors like nonlinear effects of photoelectric response of the powermeter and deviation of collimated beam is simulated. And the reason why the fitting light intensity method can not measure the retardance at 180° of non-achromatic waveplates accurately is also analyzed detailly. Under the simulation of the spectral analysis method measuring the retardance of waveplates, we also simulate the influence caused by some random errors such as light source intensity jetter, wavelength monochromaticity and motor positioning errors. Then we suppressed the random errors mentioned above in the two measurement methods in the laboratory. And the nonlinear effect of the photoelectric response of the detector is also corrected. Finally, we measured the non-achromatic
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Fan WAN, Yue ZHONG, Zhongquan QU, Zhi XU, Hui ZHANG, Yang PENG. High-precision Measurement Methods Research of Phase Retardance of Waveplates at 0°~360°[J]. Acta Photonica Sinica, 2023, 52(5): 0552215
Category: Special Issue for Advanced Science and Technology of Astronomical Optics
Received: Aug. 30, 2022
Accepted: Nov. 18, 2022
Published Online: Jul. 19, 2023
The Author Email: ZHONG Yue (yue_zhong@ynao.ac.cn)