title: Nonresonant recirculating type II second-harmonic generator.
abstract: We show an experimental proof of concept for a nonresonant recirculation method to increase the conversion efficiency of second-harmonic generation (SHG) with type II phase matching. As much as a factor-of-4 efficiency increase compared with that of single-pass SHG is possible, provided that the recirculation length is within the coherence length of the pump laser. Nonresonant recirculating SHG may be valuable in systems in which intracavity doubling is not practicable, such as high-power cw bulk solid-state or fiber lasers.
authors.affiliation: U.S. Air Force Research Laboratory, Directed Energy Directorate, AFRL/DELO, 3550 Aberdeen Avenue SE, Kirtland Air Force Base, New Mexico 87117, USA. sean.ross@kirtland.af.mil
authors.forename: T Sean
authors.initials: TS
authors.lastname: Ross
authors.forename: Gerald T
authors.initials: GT
authors.lastname: Moore