Antonin Borot

Applications of ultrafast wavefront rotation in highly nonlinear optics

This paper provides an overview of ultrafast wavefront rotation of femtosecond laser pulses and its various applications in highly nonlinear optics, focusing on processes that lead to the generation of high-order harmonics and attosecond pulses. In this context, wavefront rotation can be exploited in different ways, to obtain new light sources for time-resolved studies, called ‘attosecond lighthouses’, to perform time-resolved measurements of nonlinear optical processes, using ‘photonic streaking’, or to track changes in the carrier–envelope relative phase of femtosecond laser pulses. The basic principles are explained qualitatively from different points of view, the experimental evidence obtained so far is summarized, and the perspectives opened by these effects are discussed.

Generation of 4.3 fs, 1 mJ laser pulses via compression of circularly polarized pulses in a gas-filled hollow-core fiber

We report the generation of 4.3 fs, 1 mJ pulses at 1 kHz using a hollow-core fiber compressor seeded with circularly polarized laser pulses. We observe up to 30% more energy throughput compared to the case of linearly polarized laser input, together with significantly improved output spectral stability. Seeding with circularly polarized pulses proves to be an effective approach for high-energy operation of the hollow-fiber compression technique.

Ultra-high-contrast few-cycle pulses for multipetawatt-class laser technology.

We report the generation of few-cycle multiterawatt light pulses with a temporal contrast of 10(10), when measured as close as 2 ps to the pulses peak. Tens of picoseconds before the main pulse, the contrast value is expected to spread much beyond the measurement limit. Separate measurements of contrast improvement factors at different stages of the laser system indicate that real contrast values may reach 10(19) and 10(14), when measured 50 and 25 ps before the pulses peak, respectively. The combination of the shortest pulse duration and the highest contrast renders our system a promising front-end architecture for future multipetawatt laser facilities.

Single attosecond pulses from plasma mirrors

We demonstrate for the first time the generation of isolated attosecond pulses from plasmas driven by few-cycle lightwaves with near-relativistic intensity. This is also the first experimental demonstration of the “attosecond lighthouse” effect.

We demonstrate for the first time attosecond time scale control of collective electron motion in overdense plasmas driven by intense waveform-controlled few-cycle laser pulses

We demonstrate for the first time attosecond time scale control of collective electron motion in overdense plasmas driven by intense waveform-controlled few-cycle laser pulses

High-harmonic generation from solid targets at 1 kHz using waveform-controlled few-cycle pulses

High-harmonic generation (HHG) from solid targets driven by ultra-high-intensity lasers is predicted to be a source of attosecond XUV pulses with shorter wavelengths and higher energies than those currently generated in gases [1,2]. A much less explored regime consists in focusing few-cycle pulses down to wavelength-limited spot sizes in order to reach the ultrahigh intensities using mJ pulse energies. This enables HHG from solid targets using waveform-controlled few-cycle pulses readily obtainable from compact kHz laser systems. Here, we show the first experimental demonstration of HHG from solid targets using intense CEP-controlled two-cycle laser pulses.

Few-Cycle Ultrahigh-Contrast Light Pulses for Single Attosecond Pulses in the Relativistic Regime

We demonstrate generation of few-cycle light pulses with an ultrahigh contrast reaching 1014 25 ps before the pulse’s peak. Irradiating solid targets with our light source, we have obtained relativistic high-order harmonics that are significantly broadened and overlapped.

Attosecond control of collective electron dynamics in plasmas

We demonstrate for the first time attosecond time scale control of collective electron motion in overdense plasmas driven by waveform-controlled few-cycle laser pulses