Nonradiative Spectral and Spatial Energy Transfer in Ruby

Abstract

The first experimental evidence for distinct spectral and spatial energy transfer in ruby via nonradiative coupling is presented. Monochromatic laser excitation of the $R_1$ line results in a rise of the inhomogeneous background on a millisecond time scale, consistent with a one-phonon—assisted process and contrary to recent theory. However, time-resolved studies of trap fluorescence suggest a rapid, coherent, spatial transfer within the $R_1$ line which does not shift frequency.