Efficient spectral conversion and temporal compression of femtosecond pulses in SF_6

An uniquely high conversion efficiency of fundamental radiation from a Ti:sapphire laser to a supercontinuum is achieved through filamentary propagation in sulfur hexafluoride (SF6) to generate a uniform over-octave spectrum. Two different parts of the supercontinuum, firstly around the fundamental wavelength of 800 nm and secondly within the newly generated frequency range around 550 nm, are shown to be compressible down to minimal pulse duration of about 10 fs demonstrating a potential of the method for single-cycle pulses generation.