High-power few-cycle near-infrared OPCPA for soft X-ray generation at 100 kHz

TL;DR

This paper reports a high-power, high-repetition-rate near-infrared OPCPA system producing few-cycle pulses, enabling efficient soft X-ray generation at 100 kHz with over 21 GW peak power.

Contribution

It introduces a novel high-power, high-repetition-rate OPCPA architecture with programmable pulse shaping and demonstrates efficient soft X-ray generation at 100 kHz.

Findings

Achieved 35 W average power with near-transform-limited 9.3-fs pulses.

Demonstrated soft X-ray generation up to 190 eV photon energy.

Implemented cascaded second-harmonic generation for efficient pump pulse shaping.

Abstract

We present a near-infrared optical parametric chirped-pulse amplifier (OPCPA) and soft X-ray (SXR) high-harmonic generation system. The OPCPA produces few-cycle pulses at a center wavelength of 800 nm and operates at a high repetition rate of 100 kHz. It is seeded by fully programmable amplitude and phase controlled ultra-broadband pulses from a Ti:sapphire oscillator. The output from the OPCPA system was compressed to near-transform-limited 9.3-fs pulses. High-power operation up to an average power of 35 W was achieved, and a fully characterized pulse compression was recorded for a power level of 22.5 W, demonstrating pulses with a peak power greater than 21 GW. We demonstrate that at such high repetition rates, spatiotemporally flattened pump pulses can be achieved through a cascaded second-harmonic generation approach with an efficiency of more than 70%, providing a compelling OPCPA architecture for power-scaling ultra-broadband systems in the near-infrared. The output of this 800-nm OPCPA system was used to generate SXR radiation reaching 190 eV photon energy through high-harmonic generation in helium.