title: Experimental observation on spectrum evolution of femtosecond pulses in filamentation.
abstract: We present an experimental observation on spectrum evolution of femtosecond pulses in filamentation by introducing a hollow fiber as a probe and moving it along the filament. The results show that at a particular position of the filament, the pulse spectrum from the hollow fiber expands to its maximum, which corresponds to the shortest pulse duration existing in the filament. The influence of gas pressure on the spectrum broadening is also examined.
authors.forename: Shiying
authors.initials: S
authors.lastname: Cao
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Wenjie
authors.initials: W
authors.lastname: Huang
authors.forename: Lu
authors.initials: L
authors.lastname: Chai
authors.forename: Chingyue
authors.initials: C
authors.lastname: Wang
authors.forename: Jianjun
authors.initials: J
authors.lastname: Yang
authors.forename: Xiaonong
authors.initials: X
authors.lastname: Zhu
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhang