Stepwise multiphoton excitation of the 4f25d configuration in Nd3+: YLF

Stepwise multiphoton excitation of the 4f25d configuration of Nd3+: YLF via intermediate levels in the 4f3 configuration is investigated with nanosecond laser pulses. Strong UV and VUV fluorescence from the 4f25d configuration is observed as a result of three-photon absorption of 532 nm laser pulses from a frequency doubled Nd: YAG laser. Excitation spectra from 520–536 nm show that the efficiency of the three-photon excitation of the 4f25d configuration is maximized at 521 nm and 526 nm.