title: Generation of high contrast and high spatial quality idler from a low-gain optical parametric amplifier.
abstract: The temporal contrast of a regeneratively amplified, sub-picosecond pulse is enhanced by employing a low-gain optical parametric amplification stage self-pumped by the second harmonic of the pulse. Through careful characterization of the two related nonlinear processes and optimization of the non-collinear geometry, a robust high-contrast idler pulse has been generated, with excellent spatial quality in both the near and far field. The overall energy conversion efficiency exceeds 14%, with 33% intensity conversion efficiency. The temporal cleaning is implemented without any bandwidth losses or spectral shift and produces approximately 20% temporal shortening. These experimental findings are in excellent agreement with numerical calculations.
authors.forename: A B
authors.initials: AB
authors.lastname: Sharba
authors.forename: G
authors.initials: G
authors.lastname: Nersisyan
authors.forename: M
authors.initials: M
authors.lastname: Zepf
authors.forename: N H
authors.initials: NH
authors.lastname: Stuart
authors.forename: R A
authors.initials: RA
authors.lastname: Smith
authors.forename: M
authors.initials: M
authors.lastname: Borghesi
authors.forename: G
authors.initials: G
authors.lastname: Sarri