CE3+-ACTIVATED FLUORIDE-CRYSTALS AS PROSPECTIVE ACTIVE MEDIA FOR WIDELY TUNABLE ULTRAVIOLET ULTRAFAST LASERS WITH DIRECT 10-NS PUMPING

New possibilities have been investigated for recently developed solid-stab tunable ultraviolet (UV) laser materials such as Ce3+ ion-activated LuLiF4 (LLF) and LiCaAlF6 (LiCAF). With their broad-gain width, demonstrated reliability, and high efficiency, they are attractive for ultrashort pulse generation and amplification. To prove that, we have demonstrated UV picosecond-pulse amplification using Ce:LLF. For such new laser materials, we proposed a passive self-injection seeding scheme for the direct generation of short-pulse trains, which does not require CW-operation capability or an external short-pulse seeding laser, Using this simple scheme, a UV sub-nanosecond pulse train is directly and passively generated from Ce:LLF pumped by a standard 10-ns KrF excimer laser, and Ce:LiCAF pumped by the fourth harmonic of a conventional 10-ns Q-switched Nd:YAG laser.