Vacuum Ultraviolet Fluorescence Spectroscopy of Nd~(3+):LaF_3 Using Femtosecond Extreme Ultraviolet Free Electron Laser

摘要

Time-resolved vacuum ultraviolet (VUV) fluorescence was observed from a Czochralski method-grown Nd~(3+):LaF_3 crystal excited by 61 nm femtosecond pulses from the extreme ultraviolet free-electron laser (EUV-FEL). The 172nm fluorescence peak exhibited double exponential fluorescence decay with slow and fast decay components of 6.7 and 1.9 ns, respectively. The spectral profile is similar to those previously reported, but the double exponential nature has never been attained using conventional short-wavelength pulsed lasers. Our results demonstrate the importance of the EUV-FEL for short-wavelength spectroscopy, not just for rare-earth-doped fluorides but also for wide-band-gap semiconductors such as AlGaN.