Pulse characterization for the long path laser at LLL

Characteristics of the pulse produced by the Laboratory's Long Path Laser are reported. The pulse was studied at the output of the oscillator, the rod-amplifier chain, and the multi-pass disk amplifier. Diagnostic instruments included a Laboratory-built 10-psec resolution streak camera and a high resolution 3.4-m Ebert spectrograph. The oscillator and rod-amplifier chain outputs show strong, regular 28 psec intensity modulation produced by mode beating in the oscillator. The spectrum at each position is a regular series of lines whose wavelength separations correspond to the temporal structure observed with the streak camera. The modulation is smoothed by the disk amplifier and the spectrum is distorted and broadened. Time-resolved spectra were recorded at the output of the rod chain and the disk amplifier. Pronounced spectral differences observed at these two positions correspond to the intensity modulation smoothing observed with the streak camera after nine passes through the disk amplifier. (U.S.)