We demonstrate a non-contact, spectroscopic technique to measure
the temperature change of semiconductors with very high precision.
A temperature resolution of less than 100 μK has been obtained with
bulk GaAs. This scheme finds application in experiments to study
laser cooling of solids. We measure a record external quantum
efficiency of 99% for a GaAs device.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.