8.6 GHz Q-switched mode-locked waveguide lasing based on LiNbO 3 crystal embedded Cu nanoparticles

We report on the synthesis and features of copper (Cu) nanoparticles (NPs) embedded into LiNbO3 crystal. A linear optical absorption that peaked at 613 nm is observed, which correlates to the localized surface plasmon resonance (LSPR) effect. In addition, the Cu NPs embedded LiNbO3 (CuNP:LN) possesses ultrafast saturable absorption properties at a wavelength of 1 mu m. Based on these enhanced nonlinear optical properties, CuNP:LN is applied as a saturable absorber (SA) for pulsed laser generation in a waveguide laser system. Under an optical pump, the 8.6 GHz fundamentally Q-switched mode-locked laser operation has been efficiently implemented based on a Nd:YAG cladding waveguide fabricated by femtosecond laser writing. The measured pulse duration is as short as 55 ps and the slope efficiency is up to similar to 22.7%. This work suggests the promising application of LiNbO3 crystal embedded Cu NPs for ultrashort pulse generation. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement