Automated polarimeter–macroscope for optical mapping of birefringence, azimuths, and transmission in large area wafers. Part I. Theory of the measurement

Abstract

A computer-controlled polarimeter–macroscope has been developed to measure birefringence (phase retardation), the principal azimuths and transmission in large area (up to 6 in. diameter) wafers. It consists of two HR-type linear polarizers which can be rotated simultaneously by a stepper motor versus an immobile wafer. The transmission axes of the polarizers can be set at either 90° or 0° (polariscopic mode) or at 45° (polarimetric mode). The ability of observing samples’ images in the polariscopic mode can be useful for, e.g., quick detection of macroscopic defects. In the polarimetric mode the arrangement is capable of collecting input data through a video frame grabber (VFG)/TV camera detecting system and calculate three maps as stated above within a fraction of a minute. In usual circumstances, using a VFG with 256 grey levels enables determination of birefringence with an error not greater than approximately 5×10−7, whereas errors of azimuths and transmission are of a fraction of a degree and of a percent, respectively. In this part of the work a theory of the method and a detailed error analysis are presented.

Polarimetric imaging of amyloid

“…The Metripol microscope with mechanical light modulation was introduced by Glazer et al (1996) (see Section 4.2). Other comparable techniques have also appeared during the 1990 s (Noguchi et al, 1992;Otani et al, 1994;Pezzaniti and Chipman, 1995;Bajor et al, 1995;Zhu et al, 1999).…”

<title>Investigation of thermal annealing by gamma irradiation at room temperature in LiNbO<formula><inf><roman>3 </roman></inf></formula>crystals</title>

“…The three optical methods have been used : an automated polarimeter (refs. [1,2]) having the capacity of measuring the three maps on the entire sample area (birefringence, the principal azimuth (one of the principal residual stresses in the case of birefringence induced by residual stresses), and transmission), an automated spectropolarimeter (refs. [3][4][5]) utilizing a novel technique of mapping of parameters associated with the birefringence optical dispersion, and optical spectroscopic measurements of the so-called additional absorption.…”

Measurement of small birefringence and loss in a nonlinear single-mode waveguide

“…The simplest method involves an imaging technique that examines scattered light out-of-plane similar to that described in Ref. 17. 45°polarized light at the input will split into two components along the polarization axes; since the medium is birefringent, the resulting polarization will rotate along the length of the device.…”