Effects of chirp of the white-light continuum seed on the pulse characteristics of collinear femtosecond optical parametric amplifiers

Abstract

The influence of the chirp of the white-light continuum seed on the pulse characteristics of femtosecond optical parametric amplifiers (OPAs) is studied. Here, we focus on collinear OPAs based on type-I phase-matched BBO crystals. By numerical simulations, we investigate the evolution of the pulse-width, spectral bandwidth and time-bandwidth-product (TBP) of the amplified signal pulses with respect to the chirp of the white-light continuum seed pulses. In particular, we show that by manipulating the white-light continuum seed pulses to be highly chirped, nearly transform-limited optical pulses can be directly obtained from OPAs, without requiring dispersion-compensation elements. Our study demonstrates that chirp management offers a concise and effective technical route for obtaining nearly transform-limited, narrowband optical pulses from femtosecond OPAs, which would benefit many applications, including nonlinear imaging and spectroscopy.