Abstract

The quasi-cw "moving focus" model¹ has had much success in treating the self-focusing of nanosecond pulses. For self-focusing of shorter pulses, one expects that group velocity dispersion (GVD) will become increasingly important. Recent observations using weakly focused femtosecond pulses in noble gases have shown anomalous periodic spectral modulation in single-shot continuum generation.^2-4 In attempting to explain this, Strickland and Corkum⁴ have suggested that normal GVD results in the limitation of catastrophic self-focusing.

© 1992 Optical Society of America