We experimentally demonstrate that by use of a phase plate that is placed between an adjustable aperture and a focusing lens, the length of the filament can be dramatically extended in air with a femtosecond laser pulse. In addition, the far-field beam profile captured after the filament indicates that the supercontinuum is strongly confined on axis, and a single filament appears to be attainable at relatively high input pulse power when the phase plate is used.
© 2009 Optical Society of America
Original Manuscript: September 29, 2009
Manuscript Accepted: November 3, 2009
Published: November 30, 2009
Yuxi Fu, Hui Xiong, Han Xu, Jinping Yao, Bin Zeng, Wei Chu, Ya Cheng, Zhizhan Xu, Weiwei Liu, and See Leang Chin, "Generation of extended filaments of femtosecond pulses in air by use of a single-step phase plate," Opt. Lett. 34, 3752-3754 (2009)