Determination of retardation parameters of multiple-order wave plate using a phase-sensitive heterodyne ellipsometer

Abstract

To characterize the linear birefringence of a multiple-order wave plate (MWP), an oblique incidence is one of the methods available. Multiple reflections in the MWP are produced, and oscillations in the phase retardation measurement versus the oblique incident angle are then measured. Therefore, an antireflection coated MWP is required to avoid oscillation of the phase retardation measurement. In this study, we set up a phase-sensitive heterodyne ellipsometer to measure the phase retardations of an uncoated MWP versus the oblique incident angle, which was scanned in the x-z plane and y-z plane independently. Thus, the effect on multiple reflections by the MWP is reduced by means of subtracting the two measured phase retardations from each other. As a result, a highly sensitive and accurate measurement of retardation parameters (RPs), which includes the refractive indices of the extraordinary ray n(e) and ordinary ray n(o), is obtained by this method. On measurement, a sensitivity (n(e),n(o)) of 10(-6) was achieved by this experiment setup. At the same time, the spatial shifting of the P and S waves emerging from the MWP introduced a deviation between experimental results and the theoretical calculation.

Two-Dimensional Distributions of Five Cell Parameters of Twisted Nematic Liquid Crystal Device by Numerical Photometric Ellipsometer

“…The calibration step for the QWP is critical to ensure the accuracy of TNLCD cell parameter characterization in this method. 14,22) Following the calibration step, the TNLCD was then inserted into a laser beam at normal incidence and was placed after the QWP, as shown in Fig. 1.…”

“…Experimentally, this proposed method is based on a photometric ellipsometer, which measures the intensity response rather than the AC heterodyne signal, as in our developed interferometric ellipsometer. 11,13,14,22) The 2D distributions of all five cell parameters are available simultaneously by using two identical CCD cameras in the NPE to measure p-and s-polarization components at the same time. However, synchronizing the speed of rotation of the QWP and the frame rate of the CCD camera is important in this method for real-time measurement.…”

Development of a full-field polarization interferometer for measurement of wafer surface profile

“…This interference intensity is captured by a polarization camera [5]. According to Jones calculation [6][7], the interference intensity I can be expressed as follows:…”

A Birefringent-Refraction Transducer for Measuring Angular Displacement Based on Heterodyne Interferometry

“…Phase measurements based on angle scanning methods have been proposed to measure the retardation parameters of the multiple-order wave plate [14], and the liquid crystal cell parameters (pretilt angle and the cell gap) [15]. The results of studies measuring retardation parameters show that phase delay is deeply dependent on crystal orientations [14].…”