
%0 Journal Article
%A Stedman, GE 
%A Bilger, HR 
%A Ziyuan, Li 
%A Poulton, MP 
%A Rowe, CH 
%A Vetharaniam, I 
%A Wells, PV 
%T Canterbury Ring Laser and Tests for Nonreciprocal Phenomena
%J Australian Journal of Physics
%D 1993/02/01
%V 46
%N 1
%P 87-102
%K 
%R https://doi.org/10.1071/PH930087
%U https://www.publish.csiro.au/paper/PH930087 
%X An historic and simple experiment has been revitalised through the availability of supercavity mirrors and also through a heightened interest in interferometry as a test of physical theory. We describe our helium-neon ring laser, and present results demonstrating a fractional frequency resolution of 2·1x10-18 (1·0 mHz in 474 THz). The rotation of the earth unlocks the counterrotating beams. A new field of spectroscopy becomes possible, with possible applications to geophysical measurements such as seismic events and earth tides, improved measurements of Fresnel drag, detection of ultraweak nonlinear optical propert~es of matter, and also searches for preferred frame effects in gravitation and for pseudoscalar particles. 
