A field calibration method to eliminate the error caused by relative tilt on roll angle measurement

A high-precision measurement of small roll angular displacements based on AOMs and its error impact analysis

“…But the magnification decreases greatly when θ deviates only 0.73° from the position of θ = 14° and α is set as 87.1°, that is, the magnification would decrease from 1057 to 115. Thus, to obtain a good magnification, θ is searched within an interval of less than 1.46° to ensure that a magnification better than the magnification of K α = 114 in the previous research [25][26][27], can be found. In the experiments, the HWP is mounted on a rotatable plate frame and θ is determined within the interval of 1° to bring the magnification to greater than 211.…”

“…The polarization phase detection methods have been adopted by many researchers because of their advantages of having a simple structure and high resolution. Enhanced resolution approaches and error analysis based on polarization phase detection were also studied in our previous work [19,[25][26][27][28]. But due to the frequency-difference fluctuation and time difference between the photodetectors in the measurement and reference beams, the phase shift difference fluctuates greatly, which worsens the measurement accuracy.…”