Enhanced ((3))(X) interactions of unamplified femtosecond Cr : forsterite laser pulses in photonic-crystal fibers

摘要

Enhancement of nonlinear optical interactions in the core of a photonic-crystal fiber allows several X(3) processes to be simultaneously observed in the field of unamplified 30-fs pulses of a Cr:forsterite laser. Subnano-joule fundamental-radiation pulses of this laser experience spectral broadening arising from self-phase modulation and generate the third harmonic at 410-420 nm. Third-harmonic pulses also appear spectrally broadened at the output of the fiber as a result of the cross-phase-modulation effect. This catalog of enhanced chi((3)) processes observed in photonic-crystal fibers opens the way for using such fibers for frequency conversion of low-energy femtosecond pulses with simultaneous chirp control and subsequent pulse compression. (C) 2002 Optical Society of America. [References: 47]