1.3 μm passively Q-switched mode-locked laser with Fe3O4 nanoparticle saturable absorber

Abstract

Abstract Fe3O4 nanoparticles (FONP) are made into saturable absorbers and assembled into the resonant cavity, for the first time, and passively Q-switched mode-locked (QML) pulse output is realized in a 1.3 μm all-solid-state laser. When the pump power increases to 8 W, the repetition frequency of the Q-switched pulse increases from 47 kHz to 116 kHz, the pulse width changes from 1.137 μs to 767 ns, and the corresponding single pulse energy is 1.2 μJ. At the same time, the passively QML operation was observed on the oscilloscope, with a pulse repetition frequency of 154.5 MHz and a pulse width of 660 ps. Our experiments demonstrate that FONP exhibits good nonlinear optical characteristics in the 1.3 μm waveband, and has the potential to realize giant ultrashort and multiwavelength tunable pulse output in all-solid-state pulsed lasers.