Generation of high-power femtosecond pulses near 532 nm

Abstract

High-power ultrashort pulses in the visible and ultraviolet spectral range have important applications in filament nonlinear optics, micromachining, and ultrafast spectroscopy of molecules and biological materials. By simultaneously applying the techniques of achromatic phase matching (APM) and chirp-assisted group velocity matching (CGVM), we demonstrate a broadband frequency upconversion scheme, which is easily scalable to high energies, providing a high-contrast, high-power coherent light source for the various applications listed above. The scheme is based on an optical parametric chirped pulse amplifier (OPCPA) pumped with quasi-monochromatic 532-nm pulses, where in addition to amplifying the stretched, 250-ps, 800- nm pulses of a fs Ti:sapphire laser, broadband idler pulses at 1.6 mum are also generated. The OPCPA stage is followed by a sum-frequency converter (SFC), where the amplified 800-nm (signal) and the generated 1.6 mum (idler) pulses are mixed using APM and CGVM, producing broadband, high energy pulses near 532 nm.