Measurement of the magnetic birefringence of neon gas

Abstract

We constructed a sensitive ellipsometer to study extremely small ellipticities that are acquired by laser light when it traverses a multipass optical cavity in a 9-m-long superconducting magnet. This setup was used to measure the Cotton–Mouton constant (CCM) of neon at 514.5 nm. We find for 760 Torr (1 atm) and 25°C that CCM(Ne) = (5.5 ± 0.3) × 10−20 G−2 cm−1.