Opt. Lett. 39, 4792–4795 (2014)

The popularity of pulsed lasers in various research fields has triggered much interest in the development of schemes for shortening the duration of laser pulses. While a plethora of lasers that generate femtosecond or nanosecond pulses exist, the options for those seeking picosecond pulses are more limited. Yu-Chung Chiu and co-workers from the National Tsinghua University in Taiwan have now proposed an optical parametric scheme for simultaneously shortening laser pulses and changing their wavelength. The authors employ a passively Q-switched Nd:YAG laser (emitting 560 ps pulses at 1,064 nm) and use a nonlinear optical crystal of periodically-poled lithium niobate to perform phase-matched optical parametric generation and obtain pulses of just 80 ps at 1,546 nm. Furthermore, by using a non-poled lithium niobate crystal instead, the researchers generated pulses at 1,070 nm with nearly zero wavelength conversion that had their pulse length shortened by a factor of 3.6 compared with the original pulse lengths of 560 ps. The researchers note that their converted pulses have a smooth temporal shape and no unwanted satellite pulses were observed following conversion.