Carrier-envelope phase effects on the strong-field photoemission of electrons from metallic nanostructures

Sharp metallic nanotapers irradiated with few-cycle laser pulses are emerging as a source of highly confined coherent electron wavepackets with attosecond duration and strong directivity. The possibility to steer, control or switch such electron wavepackets by light is expected to pave the way towards direct visualization of nanoplasmonic field dynamics and real-time probing of electron motion in solid state nanostructures. Such pulses can be generated by strong-field induced tunneling and acceleration of electrons in the near-field of sharp gold tapers within one half-cycle of the driving laser field. Here, we show the effect of the carrier-envelope phase of the laser field on the generation and motion of strong-field emitted electrons from such tips. This is a step forward towards controlling the coherent electron motion in and around metallic nanostructures on ultrashort length and time scales

Analysis of laser radiation using the Nonlinear Fourier transform

Modern high-power lasers exhibit a rich diversity of nonlinear dynamics, often featuring nontrivial co-existence of linear dispersive waves and coherent structures. While the classical Fourier method adequately describes extended dispersive waves, the analysis of time-localised and/or non-stationary signals call for more nuanced approaches. Yet, mathematical methods that can be used for simultaneous characterisation of localized and extended fields are not yet well developed. Here, we demonstrate how the Nonlinear Fourier transform (NFT) based on the Zakharov-Shabat spectral problem can be applied as a signal processing tool for representation and analysis of coherent structures embedded into dispersive radiation. We use full-field, real-time experimental measurements of mode-locked pulses to compute the nonlinear pulse spectra. For the classification of lasing regimes, we present the concept of eigenvalue probability distributions. We present two field normalisation approaches, and show the NFT can yield an effective model of the laser radiation under appropriate signal normalisation conditions

Strong-field photoemission from nanostructuresdriven by few-cycle mid-infrared fields

We present strong-field photoemission from plasmonic nanotips driven by ultrashort pulses at wavelengths of 0.8-8μm, reaching Keldysh parameters down to 0.1. We identify a sub-cycle acceleration regime that is exclusive to confined fields in nanostructures

Strong-field photoemission from nanostructuresdriven by few-cycle mid-infrared fields

We present strong-field photoemission from plasmonic nanotips driven by ultrashort pulses at wavelengths of 0.8-8μm, reaching Keldysh parameters down to 0.1. We identify a sub-cycle acceleration regime that is exclusive to confined fields in nanostructures

Ultrafast Single-Shot Measurements in Modulation Instability and Supercontinuum

International audienceThe real-time measurement of ultrafast noisy processes is challenging because it requires single-shot resolution, broadband fidelity and long-record length. It is especially difficult to measure fluctuations in the optical supercontinuum, a white light source that can span over an octave in bandwidth