Efficient tunable LiF:F⁻₂ crystal lasers

Optimization of the technology of preparation of active elements made of LiF crystals containing color centers ensured high values of the parameters of wide-band generation of light by the color centers in a nonselective resonator pumped with YAG:Nd 3+ laser radiation ( λ = 1.064 μ). The efficiency measured relative to the incident pump energy was 25%, the efficiency of energy absorption was 32%, and the differential efficiency was 50%. The lasing band had a maximum at λ =1.17 μ and the half-width was Δλ >1000 cm −1 . Stimulated emission of radiation by the centers was observed when the pump laser was operated under free-running conditions (smooth pulses) and the efficiency measured relative to the incident pump energy was then 0.5%. An efficient LiF: laser with a spectrally narrow (<0.05 nm) and continuously tunable (within the 1.09–1.23 μ range) emission line was constructed. The efficiency at the maximum of the tuning curve ( λ = 1.17 μ) was 10% measured relative to the incident energy and 12% measured relative to the absorbed energy; the differential efficiency was 23%. The operating temperature of the active elements of the laser was the room value and the repetition frequency of the output pulses was up to 100 Hz.