CONTROL OF THE ND-LASER OUTPUT BY CR-DOPED Q-SWITCHES

Results of experimental investigations on controlling lasing character istics of Nd lasers (pulse width, energy and repetition rate of giant pulses, and polarization properties) with passive Q-switches based on Cr4+-doped crystals are presented. The studies were performed with bot h a flashlamp and laser-diode-pumped lasers. The possibility of this n onconventional use of passive e-switches stems from the intrinsic prop erties of Cr4+-doped crystals. The dipole moments of active centers in cubic hosts are oriented along the [001]-axes. Therefore, the process es of absorption saturation and the magnitude of residual losses displ ay orientational dependence on the angle between the polarization plan e and the crystal axes of the passive Q-switch. This paper presents th e results of the study of passive Q-switches that bleach during giant- pulse lasing in a Nd laser. We have demonstrated the possibility to co ntrol laser parameters by the rotation of a preliminarily oriented Cr4 +-doped crystal around the optical axis of the laser cavity. With a st abilized pumping power, the energy, the pulse width, and the repetitio n rate of giant pulses can be changed within an order of magnitude as functions of the angular orientation of the Q-switch.