Time-resolved measurement of electronic and vibrational nonlinear refraction in Ti:sapphire and Cr:LiSGaF

Abstract

We observe electronic and vibrational contributions in the femtosecond nonlinear response of Ti:sapphire and Cr:LiSGaF. The results suggest that nonlinear refraction is resonantly enhanced in Ti:sapphire relative to that of undoped sapphire. Cr:LiSGaF shows a substantial vibrational component and finite two-photon absorption. The implications of the nonlinear responses for short-pulse formation are discussed.