Measurement of the complex Faraday angle in thin-film metals and high temperature superconductors

TL;DR

This paper presents a sensitive polarization modulation method to measure the complex Faraday angle in thin-film metals and high-temperature superconductors across a broad temperature range using mid-infrared light.

Contribution

It introduces a novel polarization modulation technique with heterodyne detection for simultaneous measurement of Faraday rotation and ellipticity in various thin-film samples.

Findings

Measured Faraday angles in high-temperature superconductors YBCO and BSCCO.

Achieved temperature-dependent measurements from 35K to 330K.

Demonstrated technique's sensitivity in the mid-infrared spectral range.

Abstract

A sensitive polarization modulation technique uses photoelastic modulation and hetrodyne detection to simultaneously measure the Faraday rotation and induced ellipticity in light transmitted by semiconducting and metallic samples. The frequencies measured are in the mid-infrared and correspond to the spectral lines of a CO2 laser. The measured temperature range is continuous and extends from 35 to 330K. Measured samples include GaAs and Si substrates, gold and copper films, and YBCO and BSCCO high temperature superconductors.