Passive Q-switching of fiber lasers using a broadband liquefying gallium mirror

Using a nonlinear cavity element, a liquefying gallium mirror, we demonstrate stable, self-starting, passive Q-switching of both erbium and ytterbium fiber laser cavities operating at wavelengths of 1550 and 1030 nm, respectively. The performance at 1550 nm is shown to be equivalent to that achieved with a state of the art semiconductor saturable absorber designed to work at this wavelength. The results highlight the suitability of this tremendously broadband, inexpensive nonlinear medium for a wide range of passive Q-switch applications.