Phonon physics in ruby studied by optical pumping and luminescence

Two examples are treated of nonequilibriurn phonons in ruby as studied with optical pumping for generation and luminescence for detection. The first example concerns nonequilibrium 29cm(-1) and near-zone-boundary phonons generated in the nonradiative decay from higher multiplets to 2 (A) over bar(E-2) and (E) over bar(E-2). The second example shows that coherent phonons are produced by stimulated emission over the Zeeman transition within the (E) over bar(E-2) metastable doublet. (c) 2006 Elsevier B.V. All rights reserved.