title: Observation of Nondegenerate Two-Photon Gain in GaAs.
abstract: Two-photon lasers require materials with large two-photon gain (2PG) coefficients and low linear and nonlinear losses. Our previous demonstration of large enhancement of two-photon absorption in semiconductors for very different photon energies translates directly into enhancement of 2PG. We experimentally demonstrate nondegenerate 2PG in optically excited bulk GaAs via femtosecond pump-probe measurements. 2PG is isolated from other pump induced effects through the difference between measurements performed with parallel and perpendicular polarizations of pump and probe. An enhancement in the 2PG coefficient of nearly 2 orders of magnitude is reported. The results point a possible way toward two-photon semiconductor lasers.
authors: CREOL, College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, USA.
authors: Matthew
authors: M
authors: Reichert
authors: Laboratory for Photonics and Quantum Electronics, University of Iowa, Iowa City, Iowa 52242, USA.
authors: Arthur L
authors: AL
authors: Smirl
authors: Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA.
authors: Greg
authors: G
authors: Salamo
authors: CREOL, College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, USA.|Department of Physics, University of Central Florida, Orlando, Florida 32816, USA.
authors: David J
authors: DJ
authors: Hagan
authors: CREOL, College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, USA.|Department of Physics, University of Central Florida, Orlando, Florida 32816, USA.
authors: Eric W
authors: EW
authors: Van Stryland