Knowledge Bank

The heat from radiationless relaxation of electronic excitations in solids readily can be measured at low temperatures using a superconductindg bolometer as a thermometer. With pulsed dye laser excitation, the resulting heat pulses can be followed on the $10-8$ sec timescale, and their form used to infer the relaxation pathway and the characteristic excited-state lifetimes. Several examples of this effect in doped laser crystals and pure transition-metal compounds will be given.