Cascaded nonlinear frequency conversion into the deep-ultraviolet

Summary form only given. We report the first demonstration of VUV light generation through cascaded nonlinear wave-mixing using electronic nonlinearities. We also demonstrate a type of quasi-phase-matching in the UV region of the spectrum for the first time. In past work, by using a hollow-waveguide geometry for frequency conversion, we demonstrated that it is possible to achieve high efficiency conversion efficiency (13%) of ultrafast pulses to 267 nm using four-wave mixing. We also demonstrated broad-bandwidth phase-matching to generate light from 80-300 nm, using both resonant and non-resonant high-order phase matching processes. In this work, we increase the conversion efficiency to 267 nm light to 40%. This high efficiency allows the 267 nm UV light to drive a second four-wave mixing upconversion process into to the VUV with macroscopic conversion efficiency. This process upconverts light in large (1.5 eV) energy steps, (unlike processes such as antistokes Raman), and is uniquely suited for generating intense light.