A dual-loss-modulated intra-cavity frequency-doubledQ-switched andmode-locked Nd:Lu0.15Y0.85VO4/KTP green laser with a single-walled carbon nanotube saturable absorber and an acousto-opticmodulator

Abstract

By using both a single-walled carbon nanotube saturable absorber (SWCNT-SA) and anacousto-optic (AO) modulator, a dual-loss-modulated intra-cavity frequency-doubledQ-switched andmode-locked (QML) Nd:Lu0.15Y0.85VO4/KTP (KTiOPO4) green laser was demonstrated for the first time. The QML green lasercharacteristics such as the pulse width and single-pulse energy have beenmeasured for different modulation frequencies of the AO modulator (fp). In particular, in comparison with the solely passively QML greenlaser with an SWCNT-SA, the dual-loss-modulated QML green lasercan generate a more stable pulse train, a shorter pulse width of theQ-switched envelope, a greater pulse energy and a higher average peak power. Forthe dual-loss-modulated QML green laser, at a pump power of 7.9 W anda repetition rate of 10 kHz, the pulse width and the pulse energy of theQ-switch envelope and the average peak power of the QML green laser are 50 ns,20.34 µJ and 15.5 kW, respectively, corresponding to a pulse width compression of 77%, apulse energy improvement factor of six times and a QML peak power increasefactor of 16 times when compared with those for the solely passively QML greenlaser. The experimental results show that the dual-loss modulation is an efficientmethod for the generation of a stable QML green laser with an SWCNT-SA.