Intracavity pumped gain-switched broadband LiF:F2- laser

Growing application of solid state lasers brings the requirements of new wavelengths generation together with a compact simple construction of laser system. We have demonstrated compact, diode pumped Nd:YVO4/LiF:F2- nanosecond laser source operating simultaneously at 1064 and 1143 nm wavelengths. The laser based on Nd:YVO4 crystal gives an efficient output and offers various options for wavelength conversion. The LiF:F2- crystal inserted inside the resonator plays dual role of passive Q-switch for Nd:YVO4 laser, and gain medium of color center oscillator. The 52 mm long cavity consisted of 0.25% Nd3+ doped YVO4 and LiF:F2- crystal of 40% initial transmission. The resonator output coupler with curvature radius of 150 mm has 5% and 15% transmission at 1064 and 1150 nm wavelengths, respectively. The rear mirror was HR for both wavelengths and AR for 810 nm diode pumping (20 W diode bar with beam shaper). The linear polarized at both wavelengths output pulses with the energy 6 and 2 μJ at 1064 nm and 1143 nm, respectively, were detected. The corresponding pulse length (FWHM) was 6.5 ns and 4.5 ns. The pulse frequency at each wavelength was about 75 kHz. The 15 nm width of spectrum centered at 1143 nm wavelength was measured. The multimode output with divergence angles of 5.2×3.5 mrad was evidenced. The pump threshold was about 6 W and maximum mean power was 0.145 W for 18 W pump power with duty factor of 25%. This laser could be used for spectroscopic and other applications.