Phase shifter calibration in phase-shifting interferometry

Abstract

This paper describes some practical methods to calibrate the phase shifter in phase-shifting interferometry (PSI). The phase shifter used in the experiment is a piezoelectric transducer (PZT) that has a nonlinearity of <l%. Using the quantitative method described in this paper, the repeatability in the measurement of the phase-shifting angle is ˜9.046 o rms, and the 3σ 3σ value is 0.139 o. A calibration-insensitive phase calculation algorithm is discussed and compared with other synchronous detection equations (e.g., the three-bucket or the four-bucket method). Experimental results verify the calibration-insensitive mechanism of the self-calibrating algorithm.

Opto-Mechanical Properties of PTFE Fibres Using Phase Shifting Interferometry

“…The PZT was calibrated for getting the proper phase shift between the data frames. The phase-lock and the sinusoidal extreme sensing methods were applied for PZT calibration [16]. In this method five phase-shifted intensity profiles of tilt fringes were displayed simultaneously on the screen of the monitor.…”

“…By changing the voltage applied to the PZT, a continuous phase-shift in the range of 0 -2π can be obtained. The calibration of the PZT was done, for obtaining accurate phase measurements, using the phase-lock method with an accuracy of ±0.052 rad [16]. Two polarization states were obtained using a polarizer P and an analyzer A.…”

“…The principal phase errors of PSI technique are non-linearities in the movement of the PZT performing the phase-stepping and miscalibration of phase step [16]. This phase error can be decreased by applying the compensated phase shifting algorithms [16]- [18].…”

“…This phase error can be decreased by applying the compensated phase shifting algorithms [16]- [18]. There are different advantages of the PSI methods such as: rapid measurement, high measurement accuracy and good results even with low contrast fringes and the results independent of intensity variations across the pupil.…”

Surface Form Measurement Using Single Shot Off-axis Fizeau Interferometry

“…The deviation was estimated to be in the range of 5.0x10 -5 mm. The third source of uncertainty may be due to the nonlinearity of the voltage used in the experiment [20][21]. The standard deviation of the voltage from the mean was 0.025 V; this corresponds to a height of 1.0x10 -5 mm.…”