7B4 - Absorption and emission properties of optically pumped ruby

Several experiments on optically excited ruby are described. First, absorption transitions initiated from the metastable states,tmin{2}max{3}2Eandtmin{2}max{3}2T1, are investigated in the photon energy range from 5500 to 45 000 cm-1. The absorption spectrum of these excited states is determined in bothπ-and σ-polarizations and assignments for the observed absorption bands are achieved. Obtained results are compared with other experiments reported in the literature. Next, emission properties of pink ruby are studied in the region near theRlines. The emission spectrum is determined point by point by means of intense flash excitation. The observed weak bands are ascribed to theR'and phonon assistedRtransitions. Laser actions in these bands are discussed and experimental results on phonon terminated laser amplification are presented. An experiment using a giant pulse as an excitation source reveals that the transition time fromtmin{2}max{3}2Etotmin{2}max{3}2T1is shorter than a fraction of 1μs at room temperature.