Supercontinuum generation in atmospheric-pressure nitrogen and oxygen by intense ultrafast Ti:sapphire laser

Summary form only given. The largest blue-shift in air under a focused intense laser beam has attracted much attention. We report the supercontinuum generation in 1-atm nitrogen and oxygen respectively. The experiments were carried out with a 10-Hz Ti:sapphire chirped-pulse amplification laser system. It delivered pulses of 10 mJ maximum energy and wavelength centered at 805 nm. In the experiments, the laser pulses were focused with a lens (f=11 cm) into a cell which was filled with 1-atm nitrogen or oxygen; the ionization was checked by a pair of electrodes with applied 36 V DC voltage. The transmitted laser radiation was recollimated with a fused-silica lens and sent into a spectrometer coupled with a charge-coupled device camera with a resolution of 0.327 nm. The detection of the spectral component was time integrated, and the results were analyzed with a linked personal computer.