The picosecond time scale pedestal of a multiterawatt femtosecond laser pulse is investigated experimentally and analytically. The origin of the pedestal is related to the finite bandwidth of the laser system. By deliberately introducing a modulated spectrum with minima that match this limited bandwidth, the pedestal can be reduced, with no deleterious effect on the main pulse. Using this technique, we experimentally demonstrate a subpicosecond scale order of magnitude enhancement of contrast ratio while preserving the energy in the main pulse.
Lasers and Laser Optics
Original Manuscript: July 3, 2013
Revised Manuscript: August 6, 2013
Manuscript Accepted: August 15, 2013
Published: September 12, 2013
D. Kaganovich, J. R. Peñano, M. H. Helle, D. F. Gordon, B. Hafizi, and A. Ting, "Origin and control of the subpicosecond pedestal in femtosecond laser systems," Opt. Lett. 38, 3635-3638 (2013)