De Vine, GlennMcClelland, David E.Close, John D.Gray, Malcolm B.2016-05-192016-05-190146-9592http://hdl.handle.net/1885/101451We present an experimental technique enabling mechanical-noise free, cavity-enhanced frequency measurements of an atomic transition and its hyperfine structure. We employ the 532nm frequency doubled output from a Nd:YAG laser and an iodine vapour cell. The cell is placed in a traveling-wave Fabry-Perot interferometer (FPI) with counter-propagating pump and probe beams. The FPI is locked using the Pound-Drever-Hall (PDH) technique. Mechanical noise is rejected by differencing pump and probe signals. In addition, this differenced error signal gives a sensitive measure of differential non-linearity within the FPI.This research was completed at the Center for Gravitational Physics and the Center for Quantum Atom Optics supported by the Australian Research Council and the Australian Capital Territory Government.© 2005 Optical Society of AmericaKeywords: Demodulation; Frequencies; Mirrors; Neodymium lasers; Nonlinear optics; Pumping (laser); Spurious signal noise; Atomic transition; Folded ring cavity (FRC); Laser spectroscopy; Probe signals; Laser optics2004-11-1010.1364/OL.30.0012192016-06-14