Applications of Ultrafast Spectroscopy to Solid State Laser Materials

Abstract

Workers in the field of luminescence spectroscopy have, for the most part, been constrained to the role of observer: following excitation with light, the crystal is allowed to tell its own story while we merely record its unfolding. With the advent of femtosecond lasers and new pulse-shaping techniques, we now have the possibility of controlling the outcome of the story. This article will focus on some possible uses of ultrafast spectroscopy for uncovering the physics of rare earth- and transition metal-doped ionic insulating crystals, or solid state laser materials. Specifically, we will show how coherent wavepacket excitation and mode selective excitation can be used to investigate and to control the nonradiative processes, such as multiphonon decay, vibronic transitions, and phonon-assisted energy transfer.