K. Möhle

Rotating optical cavity experiment testing Lorentz invariance at the 10-17 level

We present an improved laboratory test of Lorentz invariance in electrodynamics by testing the isotropy of the speed of light. Our measurement compares the resonance frequencies of two orthogonal optical resonators that are implemented in a single block of fused silica and are rotated continuously on a precision air bearing turntable. An analysis of data recorded over the course of one year sets a limit on an anisotropy of the speed of light of

High performance iodine frequency reference for tests of the LISA laser system

\ensuremath{\Delta}c/c\ensuremath{\sim}1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17}

Testing Lorentz Invariance by Comparing Light Propagation in Vacuum and Matter

. This constitutes the most accurate laboratory test of the isotropy of

Highly stable piezoelectrically tunable optical cavities

c

Ultra-Stable Cryogenic Optical Sapphire Resonators for Tests of Fundamental Physics

to date and allows to constrain parameters of a Lorentz violating extension of the standard model of particle physics down to a level of

The Space-Time Asymmetry Research (STAR) program

{10}^{\ensuremath{-}17}

A MODERN MICHELSON-MORLEY EXPERIMENT USING ACTIVELY ROTATED OPTICAL RESONATORS

.

Modern Optical Tests of Special Relativity

Forthcoming space missions like the Laser Interferometer Space Antenna (LISA) or the Space-Time Asymmetry Research (STAR) project call for optical frequency references with high frequency stability better than 10-14 at averaging times longer than 1000 s. Since Nd:YAG lasers are planned to be used on these missions, new interest has arisen in the frequency stabilization of Nd:YAG lasers to hyperfine transitions in molecular iodine. Iodine stabilized lasers offer an absolute optical frequency reference with high frequency stability and low sensitivity to temperature fluctuations and magnetic fields in relative simple setups. Here we present our iodine frequency standard using modulation transfer spectroscopy with a multi-pass iodine cell showing a frequency stability of 1·10-14 at 1 s averaging time.

Towards a New Generation of Ultra-Stable Molecular Optical Frequency Standards

We present a Michelson-Morley type experiment for testing the isotropy of the speed of light in vacuum and matter. The experiment compares the resonance frequency of a monolithic optical sapphire resonator with the resonance frequency of an orthogonal evacuated optical cavity made of fused silica while the whole setup is rotated on an air bearing turntable once every 45 s. Preliminary results yield an upper limit for the anisotropy of the speed of light in matter (sapphire) of \Delta c/c < 4x10^(-15), limited by the frequency stability of the sapphire resonator operated at room temperature. Work to increase the measurement sensitivity by more than one order of magnitude by cooling down the sapphire resonator to liquid helium temperatures (LHe) is currently under way.

Electromagnetic cavity tests of Lorentz invariance on Earth and in space

We have implemented highly stable and tunable frequency references using optical high finesse cavities which incorporate a piezo actuator. As piezo material we used ceramic PZT, crystalline quartz, or PZN-PT single crystals. Lasers locked to these cavities show a relative frequency stability better than