Polarization phase-shifting Newton interferometer for plane optical surface measurements

Abstract

This Letter introduces a polarization phase-shifting Newton interferometer that can be utilized for plane optical surface measurements, a setup constructed to realize the interferometer, and the experimental results from the use of the setup. The results confirm not only the validity but also the feasibility of the interferometer.

Polarization phase-shifting Newton interferometer without errors caused by polarization crosstalk

“…To compare this research with previous research [14], two interference patterns obtained in a previous study are presented in Fig. 5(a) and (b).…”

“…Besides, the phase denotes the retardation of the waves transmitting through the SPBS-air interface because they progress through an extra optical path of [14] 2 = 2h cos[sin −1 (n sin Â)]…”

“…They are immune to environmental perturbations and can be used with a low-coherence light source, they are therefore widely employed in optical applications such as flatness measurements [4,5], plane optical surface measurements [3,[5][6][7], and lens testing [3,8]. To heighten the measurement resolution of Newton interferometers, digital image processing [9][10][11][12][13] and polarization phase-shifting technique [14] have been proposed. Although polarization phase-shifting technique has an advantage over digital image processing of nanometer resolution, the measurement accuracy is limited by the errors that may occur because of polarization crosstalk of the interferometers.…”

“…Although polarization phase-shifting technique has an advantage over digital image processing of nanometer resolution, the measurement accuracy is limited by the errors that may occur because of polarization crosstalk of the interferometers. It was evaluated that the phase error due to polarization crosstalk may achieve a value of 6.9 • [14]. * Corresponding author.…”

“…Two innovative designs are incorporated into the conventional polarization phase-shifting Newton interferometer (CPPNI), so it not only possesses the original advantages [14], but also eliminates phase errors due to polarization crosstalk. In the remainder of this paper, the configuration, measurement theory, and installation of the proposed interferometer are introduced sequentially.…”