title: Ultrafast optical switching by use of fully phase-matched cascaded second-order nonlinearities in a polarization-gate geometry.
abstract: We show that cascaded second-order nonlinear-optical processes can occur in a convenient polarization-gate beam geometry. Our arrangement uses type II phase matching, and both individual second-order processes (upconversion and downconversion) are simultaneously phase matched. This geometry can be applied to efficient ultrafast optical switching. With a beta-barium borate crystal and lightly focused 250-fs, 7.3-microJ pulses, we achieve a switching efficiency of 15% and an on-off ratio of 3 x 10(4) on a pulse-length-limited time scale.
authors.forename: M A
authors.initials: MA
authors.lastname: Krumbügel
authors.forename: J N
authors.initials: JN
authors.lastname: Sweetser
authors.forename: D N
authors.initials: DN
authors.lastname: Fittinghoff
authors.forename: K W
authors.initials: KW
authors.lastname: Delong
authors.forename: R
authors.initials: R
authors.lastname: Trebino