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-activat ed LuLiF4 (LLF) and LiCaAlF6 (LiCAF). With their broad-gain width, dem onstrated reliability, and high efficiency, they are attractive for ul trashort pulse generation and amplification. To prove that, we have de monstrated UV picosecond-pulse amplification using Ce:LLF. For such ne w laser materials, we proposed a passive self-injection seeding scheme for the direct generation of short-pulse trains, which does not requi re CW-operation capability or an external short-pulse seeding laser, U sing this simple scheme, a UV sub-nanosecond pulse train is directly a nd passively generated from Ce:LLF pumped by a standard 10-ns KrF exci mer laser, and Ce:LiCAF pumped by the fourth harmonic of a conventiona l 10-ns Q-switched Nd:YAG laser.