Two-mode frequency-stabilised He-Ne (633 nm) lasers: studies of short- and long-term stability

Abstract

Discusses the practical design and performance of lasers stabilised by balancing the powers in two orthogonally polarised modes. Procedures for aligning the optical system and for optimising the electronic controller are described. The performances of several types of commercial tubes have been tested over periods of over three years. A short-term (1 s) stability of 20 kHz and a long-term (several months) stability of 10 MHz have been achieved with some tubes. An additional characteristic of these lasers is their good power stability (within 0.1% over several hours).