A Sensitive Faraday Rotation Setup Using Triple Modulation

TL;DR

This paper introduces a novel triple modulation Faraday rotation technique to measure Verdet constants, demonstrating its potential for precise characterization of materials like GE-180 glass and air, with applications in polarized target experiments.

Contribution

The paper presents the first measurement of GE-180 glass's Verdet constant at multiple wavelengths using a new triple modulation method.

Findings

Verdet constants of SF57, pyrex, and air were successfully measured.

The technique achieved high sensitivity suitable for cell wall characterization.

GE-180 glass's Verdet constant follows the expected wavelength dependence.

Abstract

The utilization of polarized targets in scattering experiments has become a common practice in many major accelerator laboratories. Noble gases are especially suitable for such applications, since they can be easily hyper-polarized using spin exchange or metastable pumping techniques. Polarized helium-3 is a very popular target because it often serves as an effective polarized neutron due to its simple nuclear structure. A favorite cell material to generate and store polarized helium-3 is GE-180, a relatively dense aluminosilicate glass. In this paper, we present a Faraday rotation method, using a new triple modulation technique, where the measurement of the Verdet constants of SF57 flint glass, pyrex glass, and air were tested. The sensitivity obtained shows that this technique may be implemented in future cell wall characterization and thickness measurements. We also discuss the first ever extraction of the Verdet constant of GE-180 glass for four wavelength values of 632 nm, 773 nm, 1500 nm, and 1547 nm, whereupon the expected 1/{\lambda}^{2} dependence was observed.