Femtosecond-laser-encoded distributed-feedback color center laser in lithium fluoride single crystal

摘要

Focused infrared femtosecond laser pulses (wavelength ～800 nm, emission pulse duration 100 fs) were employed to fabricate optoelectronic devices such as waveguides, micro-gratings and laser active centers in LiF crystals. F_2 color centers of about 2 x 10~(18) cm~(-3) and refractive index change of about 1% at 633 nm were induced by the fs-laser irradiation. This technique was applied to fabricate a distributed-feedback (DFB) F_2 color center laser structure inside LiF single crystal. The LiF DFB laser exhibited laser oscillation at 707 nm at room temperature. The slope efficiency of ～10% and beam divergence of ～20 mrad were achieved.