Time-resolved excited-state electronic Raman spectrum of ruby

Abstract

Raman scattering transitions between the excited states Ē( 2E) and 2Ā( 2E) of Cr 3+ in Al 2O 3 are studied. The new technique for population decay measurements of the excited states uses a pulsed tunable dye laser as an optical pump and a cw laser as a Raman probe, plus a gated detection system. The population decay of the optically prepared states, under conditions of illumination required to record the excited state electronic Raman shift at 29 cm −1 of the ruby crystal, is faster than 20 μs. This is at least three orders of magnitude smaller than the radiative decay time of R 1,2 fluorescence of ruby for small signal intensity excitation.