title: Spectral analysis and control to obtain sub-5 fs pulses by femtosecond filamentation.
abstract: A spectral-filter method is numerically demonstrated to obtain sub-5 fs pulses by using femtosecond filamentation in fused silica. Instead of employing spectral phase compensation, by properly employing a high-pass filter to select the broadened high-frequency spectra that are located almost in phase in the tailing edge of the self-compressed pulses owing to self-steepening, as short as single-cycle pulses can be obtained. For instance, for an input pulse with a duration of 50 fs and energy 2.2 microJ, the minimum pulse duration can reach to approximately 4 fs (about 1.5 cycles) by applying a proper spectral filter.
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Zhanxin
authors.initials: Z
authors.lastname: Wang
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Liu
authors.forename: Ruxin
authors.initials: R
authors.lastname: Li
authors.forename: Zhizhan
authors.initials: Z
authors.lastname: Xu