Abstract

Recently the interest in Q-switched and mode-locked lasers has significantly grown. Passive mode-locking was recently reported in Nd:YVO₄ laser Q-switched at 1064 nm with Cr:YAG [1]. Hereby we report on what is to our knowledge the first all-solid-state, diode-pumped, Nd:YVO₄ laser efficiently Q-switched and mode-locked at 1340 nm. This operation regime was achieved using a V:YAG saturable absorber that has already been proved effective for applications in the 1.3μm telecommunication window, owing to its favourable ground- and excited-state absorption characteristics. Moreover it has a relatively fast absorption recovery time of few nanosecond that migth allows mode-locking when the resonator is properly designed. We applied a numerical model to resonators including V:YAG saturable absorber crystal to evaluate conditions that allows transition toward mode-locking and Q-switching regimes [2] in relation with some critical parameters as ratio between resonator round trip time and absorber recovery time and compared its prediction with the experimental results. We experimentally demonstrated, in qualitative agreement with the prediction, that increasing the resonator length (>0.8 m) extended microsecond trains of nearly fully-modelocked subnanosecond pulses can be generated.

© 2001 EPS