Precision synchronous polarimeter with linear response for the measurement of small rotation angles

Abstract

A synchronous polarimeter was set up for the measurement of small rotation angles of the polarization plane of light. The polarimeter is based on a polarizer–Faraday modulator–analyzer structure with a synchronous detection scheme, which produces a linear system response. The theoretical background is studied, and the system performance is investigated experimentally. We achieved an accuracy of the order of 10-4 deg, or 5 mg/dl of glucose in a 1-cm light path.