title: Analysis and suppression of parasitic processes in noncollinear optical parametric amplifiers.
abstract: The influence of parasitic processes on the performance of ultra-broadband noncollinear optical parametric amplifiers (NOPA's) is investigated for walk-off and non-walk-off compensating configurations. Experimental results with a white-light-seeded NOPA agree well with numerical simulations. The same model shows that 10% of the output energy of an amplified signal can be transferred into a parasitic second harmonic of the signal. These findings are supported by quantitative measurements on a few-cycle NOPA, where a few percent of the signal energy is converted to its second harmonic in the walk-off compensating case. This effect is reduced by an order of magnitude in the non-walk-off compensating configuration. A detailed study of the phase-matching conditions of the most common nonlinear crystals provides guidelines for designing NOPA systems.
authors.affiliation: University of Rochester, Laboratory for Laser Energetics, Rochester, New York 14559, USA. jbro@lle.rochester.edu
authors.forename: J
authors.initials: J
authors.lastname: Bromage
authors.forename: J
authors.initials: J
authors.lastname: Rothhardt
authors.forename: S
authors.initials: S
authors.lastname: Hädrich
authors.forename: C
authors.initials: C
authors.lastname: Dorrer
authors.forename: C
authors.initials: C
authors.lastname: Jocher
authors.forename: S
authors.initials: S
authors.lastname: Demmler
authors.forename: J
authors.initials: J
authors.lastname: Limpert
authors.forename: A
authors.initials: A
authors.lastname: Tünnermann
authors.forename: J D
authors.initials: JD
authors.lastname: Zuegel