Improved optical test of special relativity

A new Michelson-Morley (MM) experiment that is based on a one-year comparison of the frequencies /spl nu//sub x/ and /spl nu//sub y/ of two lasers stabilized to crossed cryogenic optical resonators (CORES) at 1064 nm. The experiment relies on a highly developed laser frequency stabilization scheme: an automatic beam positioning system continuously maximises the incoupling of laser radiation to the COREs.