Temporal and spatial effects inside a compact and CEP stabilized, few-cycle OPCPA system at high repetition rates

Abstract

We present a compact and ultra-stable few-cycle OPCPA system. In two non-collinear parametric amplification stages pulse energies up to 17 µJ at 200 kHz repetition rate are obtained. Recompression of the broadband pulses down to 6.3 fs is performed with chirped mirrors leading to peak powers above 800 MW. The parametric amplification processes were studied in detail employing (2 + 1) dimensional numerical simulations and compared to experimental observations in terms of spectral shapes, pulse energy, spatial effects as well as delay dependent nonlinear mixing products. This gives new insights into the parametric process and design guidelines for high repetition rate OPCPA systems. X. Kärtner, "High-energy pulse synthesis with sub-cycle waveform control for strong-field physics," Nat. Photonics 5(8), 475-479 (2011) Mauritsson, J. N. Andersen, H. Q. Xu, and A. L'Huillier, "Photoemission electron microscopy using extreme ultraviolet attosecond pulse trains," Rev. ©2013 Optical Society of America

Generation and Parametric Amplification of Few‐Cycle Light Pulses at Relativistic Intensities

“…Our explanation for the findings is therefore the cascading of two χ ( ) -processes, an effect that has been reported before in other experiments [143][144][145]. An exemplary interaction would be:…”

“…In fact, we achieved slightly better efficiencies in the high energy campaign presented in the next section but still not close to the theoretical predictions. On the other hand, a comparison with similar broadband OPCPA systems shows that efficiencies of 10-15 % in high gain stages are rather the rule than the exception [145,[149][150][151]. Hence, the simulations might neglect higher-order losses present in real world systems that prevent reaching higher efficiencies.…”

Carrier-envelope phase dependent high-order harmonic generation with a high-repetition rate OPCPA-system

“…The HHG setup is driven by an OPCPA system [6], sketched in Figure 1. The system comprises three main units: a broadband Ti:Saph oscillator (VENTEON), a pumping laser based on an Yb-doped fiber amplifier, and a two-stage Non-collinear Optical Parametric Amplifier (NOPA).…”

“…The current limitations in conventional amplifiers, such as gain-narrowing and thermal lensing, are avoided in parametric amplification. OPCPA technology allows for the amplification of few-cycle pulses with TW peak power [3] at low repetition rates and is particularly advantageous at high-repetition rate from hundreds of kHz [4][5][6] to few MHz [7][8][9]. Recently, OPCPA systems producing CEP-stable few-cycle pulses at high-repetition rate have been successfully used for high-order harmonic generation (HHG).…”

“…In this work, we present a HHG source driven by a compact OPCPA laser producing CEP-stable 8 fs, 10 μJ pulses, at 890 nm central wavelength, and 200 kHz repetition rate [6]. To achieve sufficiently high intensity for efficient HHG in Ar, the laser beam is tightly focused (f = 5 cm) into a high pressure effusive Ar gas jet.…”