Phase-matching in cascaded third-order frequency mixing

Summary form only given. We consider here the frequency mixing processes that result in the generation of ultrafast vacuum ultraviolet pulses. We have shown experimentally that by mixing the fundamental (800 nm) of an ultrafast Ti:sapphire laser pulse with its second harmonic (400nm) in a gas-filled hollow waveguide, very high conversion efficiency to the deep ultraviolet (267nm) is possible. We have calculated analytically the phase matching conditions for high order cascaded conversion and found three distinct mechanisms at work. We also present detailed simulations that include the effects of backconversion, self- and cross-phase modulation and spectral dispersion.