We present an analytical, computational, and experimental study of frequency mixing and propagation that takes place in the guided-wave nonlinear frequency conversion of ultrashort pulses from the near infrared to the far and the vacuum ultraviolet. In addition to the standard phase-matching conditions for frequency mixing, we observe that cascaded frequency conversion, in which one of the input frequency components is generated simultaneously, is subject to two additional phase-matching conditions. In cascaded quasi-phase matching, one of the input fields oscillates in strength with a period that matches the phase mismatch. In gain-assisted phase matching, the growth of one of the input fields results in growth of the signal, in spite of a phase mismatch for the final mixing process.
© 2002 Optical Society of America
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4180) Nonlinear optics : Multiphoton processes
(190.7110) Nonlinear optics : Ultrafast nonlinear optics
(190.7220) Nonlinear optics : Upconversion
Charles G. Durfee, Lino Misoguti, Sterling Backus, Henry C. Kapteyn, and Margaret M. Murnane, "Phase matching in cascaded third-order processes," J. Opt. Soc. Am. B 19, 822-831 (2002)