Actively initiated, quasi-passive mode-locking in a CW selfoc Nd: Glass laser

Actively initiated quasi-passive mode-locking has been achieved in a small-power CW SELFOC Nd:glass laser. Three means have been taken to enhance the pulse intensity incident on a saturable dye to a magnitude sufficient for nonlinear absorption initiation: 1) tight focusing, 2) controlled spiking oscillation, and 3) auxiliary active mode-locking. Mode-locked pulses having an 11-12-ps pulsewidth were obtained. Interpretation concerning the observed mode-locked-pulse intensity-correlation curves is presented. To obtain satellite-pulse-free mode-locked pulses, a modified mode-locking process with sufficiently long buildup time is considered.