A dual-loss-modulated intra-cavity frequency-doubled Q-switched and mode-locked Nd:Lu_(0.15)Y_(0.85)VO_4/KTP green laser with a single-walled carbon nanotube saturable absorber and an acousto-optic modulator

摘要

By using both a single-walled carbon nanotube saturable absorber (SWCNT-SA) and an acousto-optic (AO) modulator, a dual-loss-modulated intra-cavity frequency-doubled Q-switched and mode-locked (QML) Nd:Lu_(0.15)Y _(0.85)VO_4/KTP (KTiOPO_4) green laser was demonstrated for the first time. The QML green laser characteristics such as the pulse width and single-pulse energy have been measured for different modulation frequencies of the AO modulator (f_p). In particular, in comparison with the solely passively QML green laser with an SWCNT-SA, the dual-loss-modulated QML green laser can generate a more stable pulse train, a shorter pulse width of the Q-switched envelope, a greater pulse energy and a higher average peak power. For the dual-loss-modulated QML green laser, at a pump power of 7.9W and a repetition rate of 10kHz, the pulse width and the pulse energy of the Q-switch envelope and the average peak power of the QML green laser are 50ns, 20.34μJ and 15.5kW, respectively, corresponding to a pulse width compression of 77%, a pulse energy improvement factor of six times and a QML peak power increase factor of 16 times when compared with those for the solely passively QML green laser. The experimental results show that the dual-loss modulation is an efficient method for the generation of a stable QML green laser with an SWCNT-SA.