High conversion efficiency of an optical parametric amplifier pumped by 1 kHz Ti:Sapphire laser pulses for tunable high-harmonic generation

The maximum photon energy achievable in high harmonic generation is proportional to the square of the excitation wavelength. Due to this scaling, extreme ultraviolet (XUV) light generation requires intense infrared pulses as the excitation wavelength. Converting ultrafast pulses from Ti:sapphire to longer wavelengths through optical parametric amplification (OPA) provides a path to generating higher XUV photon energies; however the generation of such pulses often suffer from the low conversion efficiencies available with typical systems of ~ 30-43%.  In this work, a conversion efficiency of 50% in an OPA is obtained by combining it with a commercially available KMLabs Ti:Sapphire amplifier system. Coherent XUV light is then generated from Argon gas using the OPA pulse, and photoionization experiments are performed with the XUV spectra. This work demonstrates the generation of intense infrared pulses for the use of XUV spectra generation using a relatively simple optical setup compared to other methods.”