Pulse stretching of Q-switched lasers

Pulse stretching of a passively Q-switched ruby laser is accomplished by the introduction of a non-linear absorber into the laser cavity. Single pulses of length 150 to 400 nsec are observed. The non-linear absorption is obtained by using a Rayleigh-wing scatterer as the solvent for a bleachable dye. This approach is unique in that stretched Q-switched pulses may be obtained by the introduction of a single liquid into the laser resonator with no electronics necessary. Since the Rayleigh Frequency is within the gain lineshape of the active medium, threshold for the stimulated Rayleigh scattering is exceeded at relatively low power densities.