We demonstrate an automated polarimeter based on a rotating polarizer for the measurement of linear retardance independent of laser power and detector gain. The retardance is found when a curve is fitted to a unique normalization of the intensity response of the polarimeter over a range of input polarizer orientations. The performance of this polarimeter is optimal for measurements of quarter-wave retardance and minimal for half-wave retardance. Uncertainties are demonstrated by measurements on six stable double Fresnel rhombs of nominal quarter-wave retardance, yielding expanded uncertainties between0.031° and 0.067°. The accuracy has also been verified by blind comparisons with interferometric and modified null retardance measurement techniques.

Rotating-polarizer polarimeter for accurate retardance measurement.

An electro-optic modulator applied to a carrier frequency is used to measure the retardation of a wave plate. This method is not only suitable for any wave plate but also can be operated in real time.

https://ir.nctu.edu.tw:443/bitstream/11536/2916/1/A1993LP43300023.pdf

Method for measuring the retardation of a wave plate

Based on the heterodyne interferometric technique and the discrimination technique of using two light beams with different wavelengths, a novel method for identifying the fast axis of a wave plate and evaluating its phase retardation is presented. Some of the merits of the method, such as, a simple optical setup, high stability, better resolution, and easier operation, are presented, and the validity of the method is demonstrated.

https://ir.nctu.edu.tw:443/bitstream/11536/1075/1/A1996VE11300016.pdf

Method for determining the fast axis and phase retardation of a wave plate

Phase detection of Young’s fringes is applied to a highly precise retardation measurement. A simple common-path polarizing interferometer is used with a birefringent wedge and a polarizer. The birefringent wedge introduces a spatially linear phase difference between orthogonally polarized light and Young’s fringes are formed on an image sensor. The phase difference between the orthogonally polarized components of light is proportional to the phase of Young’s fringes. Thus, the retardation is equal to the Young’s fringes’ phase change before and after insertion of the retarder into the common-path interferometer. The phase of Young’s fringes is calculated from the Fourier cosine and sine integrals of the fringe profile. The experimental results for wave plates, a Soleil-Babinet compensator, and a Pockels cell are presented with error estimates. The accuracy of the retardation measurement is experimentally estimated to be greater than λ/2100.

High precision retardation measurement using phase detection of Young’s fringes

We present a measuring method for any wave plate retardation with fairly high precision that utilizes a laser frequency splitting technique. To avoid strong mode competition in measuring half and full wave plates, we use two separate methods: comparing adjacent longitudinal mode spacing, and phase offset with an additional quarter wave plate. Therefore any wave plate can be characterized by a single instrument, and no complicated experimental arrangement or data analysis is required. The performance of the system is demonstrated by determining the phase retardation of several samples to a precision and repeatability better than lambda/10(4); moreover, an error analysis is proposed.

Method for the measurement of phase retardation of any wave plate with high precision

We propose and discuss an optical heterodyne technique to measure the phase retardation of a wave plate. The accuracy of this measurement technique in determining the optical path difference of a quarter-wave plate is of the order of 0.1 nm, thus exceeding the accuracy of other measurement techniques.

Optical heterodyne measurement of the phase retardation of a quarter-wave plate

Optical heterodyne measurement of the phase retardation of a wave plate

This paper proposes and discusses an optical heterodyne technique to measure the phase retardation of a wave plate. The accuracy of this measurement technique in determining the optical path difference of a quarter wave plate is smaller than the wavelength of light source divided by 6000, exceeding the accuracies of other measurement techniques.

Lin Yao

Papers

Optical heterodyne measurement of the phase retardation of a quarter-wave plate

Optical heterodyne measurement of the phase retardation of a wave plate

Measuring phase retardation of wave plates: A NOVEL TECHNIQUE