Passively Q-switched 8.5-ns Pr3+:YLF laser at 640 nm

We report on short pulse generation from a passively Q-switched Pr3+:LiYF4 laser operating at 640 nm. By reducing the cavity length and utilizing Co:MgAl2O4 as the saturable absorber, we obtain the shortest pulse durations from any Q-switched Pr3+ laser. Under pumping with a frequency-doubled optically pumped semiconductor laser at a wavelength of 479.05 nm we realized (8.5 ± 1) ns long pulses at a repetition rate of 0.78 MHz from a 7.5 mm long cavity at an average output power of 1.0 W. In that case, the laser pulse energy and duration were 1.3 µJ and 8.5 ns, respectively. The highest pulse energy amounts to 1.8 µJ at a pulse peak power of 0.19 kW in 9.2 ns pulses at a repetition rate of 0.48 MHz.

Mid-Infrared Ultra-Short Pulse Generation in a Gas-Filled Hollow-Core Photonic Crystal Fiber Pumped by Two-Color Pulses

We show numerically that ultra-short pulses can be generated in the mid-infrared when a gas filled hollow-core fiber is pumped by a fundamental pulse and its second harmonic. The generation process originates from a cascaded nonlinear phenomenon starting from a spectral broadening of the two pulses followed by an induced phase-matched four wave-mixing lying in the mid-infrared combined with a dispersive wave. By selecting this mid-infrared band with a spectral filter, we demonstrate the generation of ultra-short 60 fs pulses at a 3–4 µm band and a pulse duration of 20 fs can be reached with an additional phase compensator.