Efficient 4-fold self-compression of millijoule pulses from a 1.5-μm optical parametric chirped-pulse amplifier

Anotacija

We discuss a four-stage optical parametric chirped-pulse amplifier that delivers carrier-envelope phase-stable ~1.5 μm pulses with energies up to 12.5 mJ before recompression. The system (previously reported in Opt. Lett. 34, 2498 (2009)) is based on a fusion of femtosecond diode-pumped solid-state Yb technology and a picosecond 100-mJ Nd:YAG pump amplifier. Pulses with 62 nm bandwidth are recompressed to a 74.4 fs duration, which is close to the transform limit. Here, to show the way towards a TW-peak-power single-cycle IR source, we perform detailed investigations of single-filament IR supercontinuum generation via femtosecond filamentation in noble gases. Depending on the experimental conditions, two filamentation regimes can be achieved: (i) in the filamentation regime without plasma-induced pulse self-compression, we generate 4-mJ 600-nm-wide IR supercontinua of high spatial quality supporting 8-fs pulse durations, which corresponds to less than two optical cycles at 1.5 μm; (ii) in the self-compression regime, we demonstrate self-compression of 2.2 mJ pulses down to 19.8 fs duration in a single filament in argon with a 1.5 mJ output energy and 66% energy throughput. By adapting the experimental conditions, further energy upscaling of the self-compressed pulses seems feasible. Keywords: optical parametric amplification, filamentation, pulse self-compression, intense few-cycle infrared pulses