Abstract

Broad-band vacuum ultraviolet (VUV) fluorescence on the 4fⁿ⁻¹ 5d → 4fⁿ transitions has been observed in a number of rare-earth activated fluoride hosts.¹ Ultraviolet (UV) laser oscillation on the 5d → 4f transition in Ce has been observed in a number of hosts,^2,3 and recently VUV laser oscillation at 172 nm has been reported⁴ in LaF₃:Nd³⁺ pumped by a pulsed-discharge molecular F₂ laser. A simplified energy level diagram illustrating the transitions involved, together with the F₂ laser induced VUV fluorescence spectrum⁵ for a 1% doped sample of LaF₃:Nd³⁺ is shown in Fig. 1. F₂ laser pumped rare-earth–doped fluorides, since they operate through linear processes, offer the prospect of a convenient source of intense tunable VUV laser radiation, with applications in photochemistry and photolithography.

© 1994 IEEE