STIMULATED-EMISSION AT 10 MU-M OF O-3 TRAPPED IN LOW-TEMPERATURE MATRICES - THRESHOLD MEASUREMENTS AND QUANTUM YIELD EVALUATION

The recently reported fluorescence, emitted near 10 mu m by laser exci ted ozone molecules trapped in xenon matrices, is actually a stimulate d emission. It is observed, at the 2 nu(3)-->nu(3) frequency, only if the laser pulse, which excites the nu(1) + nu(3) level, contains a suf ficient amount of energy. A similar emission is found in the other rar e gas matrices and in nitrogen, above a laser energy threshold which i s matrix dependent. Above the threshold, the emitted signal grows line arly with the laser pulse energy. An evaluation of the quantum yield i s obtained by comparison with the literature data on CO fluorescence. The characteristics of the observed emission (low directionality, lase r energy dependence, shortening, and amplification when compared to sp ontaneous emission) are discussed. (C) 1998 American Institute of Phys ics.