VUV fluorescence from Nd3+:LuLiF4 by two photon excitation using femtosecond laser

We report on the vacuum ultraviolet (VUV) fluorescence from Nd:LLF excited by three excitation sources namely: the 157-nm emission of a F2 laser, 61-nm emission of an extreme ultraviolet free electron laser (EUV-FEL), and the third harmonic (290 nm) of a Ti:sapphire laser. The optical characteristics of the dominant fluorescence peaks at about 182 nm and 186 nm has a decay time of about 38 ns and is similar for all excitation wavelengths. Further investigation revealed that the VUV fluorescence arising from the 290-nm excitation is due to two-photon absorption. Our results suggest the possibility of developing an all-solid-state vacuum ultraviolet laser via two-photon excitation.

► VUV fluorescence at 182 nm are observed from Nd:LLF with 290-nm excitation. ► Fluorescence properties from both crystals with 290-nm excitation are identical to that with F2-laser excitation. ► VUV emission with 290-nm excitation is attributed to two photon excitation mechanism.