Abstract

Filament generation in inert gases at various pressure lias become a standard technique for white continuum generation. In such experiments the laser pulses may typically propagate over many meters in the host gas. Since the bandwidth of the pulses easily approaches and, in many cases, even exceeds one octave, the spectral phase shift and the subsequent lengthening of the pulses due to dispersion of the host gases may be considerable. Although refractive indices of most of the gases are known for the ultraviolet and for the visible, but limited data are available for the near infrared, where few cycle laser pulses are typically generated. Moreover, their dependence on pressure was either not measured or only within a very limited pressure range. The most complete dispersion fonn accounting for pressure, temperature, and humidity was determined and experimentally proved for air only [1-2],

© 2007 IEEE