An 1112 nm pre-biased transversely pressurized electro-optic Q-switched laser using frequency selection and spectral filtering
摘要
To achieve high-peak-power and highly-stable pulsed laser output at 1112 nm, a birefringent filter (BF) and a Brewster window (BW) were incorporated into an 808 nm laser-diode (LD) side-pumped Nd: YAG cavity. This configuration provides triple functions of polarization control, frequency selection, and spectral filtering, effectively suppressing competing oscillations at the 1116 nm and 1123 nm lines while reducing the number of longitudinal modes at 1112 nm. Furthermore, a pre-biased transversely pressurized electro-optic Q-switching technology was employed to lower the modulation voltage of the MgO: LN crystal, thereby enhancing its extinction efficiency. At a maximum LD pump current of 100 A, an average output power of 2.386 W, a pulse width of 4.82 ns, and a peak power of 4.950 MW were measured from the 1112 nm pulsed laser with a pulse repetition frequency of 100 Hz. The corresponding pulse-to-pulse fluctuation of single-pulse energy and pulse width were ± 0.30% and ± 0.84%, respectively. At 1.0 kHz, the average power, pulse width, and peak power measured 11.389 W, 6.22 ns, and 1.831 MW, respectively, while the power and temporal fluctuation remained low at ± 0.72% and ± 1.77%. These results demonstrate that the proposed technique, which combines pre-biased pressurized MgO: LN electro-optic Q-switching with BW and BF filtering, offers a viable approach to enhancing both the peak power and stability of 1112 nm pulsed lasers.