title: Control of laser high-harmonic generation with counterpropagating light.
abstract: Relatively weak counterpropagating light is shown to disrupt the emission of laser high-harmonic generation. Harmonic orders ranging from the teens to the low thirties produced by a 30-femtosecond pulse in a narrow argon jet are "shut down" with a contrast as high as 2 orders of magnitude by a chirped 1-picosecond counterpropagating laser pulse (60 times less intense). Alternatively, under poor phase-matching conditions, the counterpropagating light boosts harmonic production by similar contrast through quasiphase matching where out-of-phase emission is suppressed.
authors.affiliation: Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Voronov
authors.forename: I
authors.initials: I
authors.lastname: Kohl
authors.forename: J B
authors.initials: JB
authors.lastname: Madsen
authors.forename: J
authors.initials: J
authors.lastname: Simmons
authors.forename: N
authors.initials: N
authors.lastname: Terry
authors.forename: J
authors.initials: J
authors.lastname: Titensor
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Peatross