Transmission of ultrashort pulses through hollow photonic-crystal fibers with passbands in the visible and infrared spectral ranges

Hollow-core photonic-crystal fibers with passbands in the range of wavelengths from 0.4 to 2.0 mum are demonstrated. Changes in the envelope and the evolution of the spectral phase and the chirp of femtosecond pulses propagating through hollow photonic-crystal fibers are experimentally studied. Envelope and phase distortions of ultrashort pulses transmitted through such fibers are shown to be controlled by the detuning of the carrier frequency of laser pulses from the central frequency of the passband in the transmission of the fiber. Near the passband edges, which map the edges of photonic band gaps of the fiber cladding, ultrashort pulses transmitted through the fiber display considerable envelope distortions, as well as frequency- and time-dependent phase shifts.