Modelocking of CW Nd:YAG laser using nonlinear polarisation evolution in type II frequency doubling crystal

Abstract
Passive modelocking of a CW diode-pumped Nd:YAG laser is reported using, for the first time, a nonlinear polarisation rotation effect in a type II crystal cut for second harmonic generation. The modelocking regime is self-starting and produces pulses of 7.3 ps duration with 1.7 W average output power.