Focusing of ultrashort sub-TW laser pulses in air - Supercontinuum emission

Abstract

Our recent work [Phys. Rev. A, 82, 013805 (2010)] clearly establishes a new regime of filamentation beyond the conventional "intensity clamping" by high-resolution spatial imaging of filaments. We present the corresponding measurements of the super continuum emission (SCE) from filaments in this regime produced by ultra short (45 fs) sub- TW (up to 0.2 TW) Ti:Sapphire laser pulses focused air under tight (f/6) focusing geometry. The intimate connection between the spatial and spectral domains in the new regime is established by investigating the spectral broadening of SCE at peak intensities exceeding 1014 W/cm2 pulses at the focus thus giving a more complete picture of this new regime in filamentary propagation of intense fs pulses. © 2011 SPIE.