基于VSe2宽带可饱和吸收体的2.8 μm Er:YAP被动调Q激光器OA

The vanadium diselenide(VSe2)powder was synthesized via a hydrothermal method,and a reflective VSe2 saturable absorber mirror was fabricated using liquid-phase exfoliation combined with a spin-coating process.Nonlinear optical characterization was performed using the open-aperture Z-scan technique at 1.06 μm and 3 μm,yielding modulation depths of approximately 6.1％and 4.9％,respectively.The results demonstrate that the VSe2 thin film exhibits broadband saturable absorption properties.To investigate its applicability as a passive fast photonic switch,the VSe2 saturable absorber was integrated into an end-pumped Er:YAP laser system operating at 2.8 μm,achieving stable passive Q-switched laser output.A stable pulse train emerged when the pump power reached 3.3 W,with an average output power of approximately 0.1 W.At a pump power of 7.3 W,the average output power increased to around 0.56 W,corresponding to an optical-to-optical conversion efficiency of approximately 11.4％.Under this condition,the pulsed laser had a repetition rate of 199.9 kHz and a pulse width of 208.6 ns.These find-ings indicate that the broadband VSe2 saturable absorber serves as an effective photonic modulator in the 1 μm to 3 μm wavelength range for achieving stable passive Q-switched laser operation,while also laying the foundation for realizing passive mode-locking in the mid-infrared spectral region.