A lifetime in the picosecond range of a nonradiatively damped electronic transition in an organic dye was measured. The method utilizes picosecond pulses from a Q-switched, mode-locked Nd-glass laser.

Abshqct-Measurements of damage to metal surfaces induced by intense nanosecond pulses of IR radiation are reported. Single-shot damage thresholds of Cu, stainless steel, molybdenum, and aluminum surfaces have been measured for various angles of incidence and the predicted increase in damage thresholds for gazing incidence optical components have been experimentally verified for the first time at 10 gm. In addition multiple-shot damage tests have been performed and practical lifetime curves for Cu mirrors have been established. The results are compared with existing theoretical models and shown to be in general agreement.

The results of multiple-pulse damage tests on copper mirrors using 1.7-ns CO2 lasers are reported. The measured reduction in the brightness reflectivity of the mirrors is shown to be correlated to the dramatic appearance of fine scale microstructure on the mirror surface. Scanning electron micrographs of this surface structure are presented and possible explanations of the effects are discussed.

A short actively mode-locked XeCl oscillator has produced 120-ps duration pulses for the first time. The pulses have an energy of 15 μJ and a modulation depth of >95%. The evolution of the pulsewidth during the mode-locked pulse train was also measured.

The results of an investigation of the time evolution of a mode-locked pulse produced by a CO2 laser passively mode locked with an In-doped Ge bleachable absorber are presented. The observed pulse shortening is explained by a simple theory of pulse compression due to the saturable absorber. Pulse durations as short as 400 ps are observed.