High Harmonic Generation in Two-Dimensional Mott Insulators

With a combination of numerical methods, including quantum Monte Carlo, exact diagonalization, and a simplified dynamical mean-field model, we consider the attosecond charge dynamics of electrons induced by strong-field laser pulses in two-dimensional Mott insulators. The necessity to go beyond single-particle approaches in these strongly correlated systems has made the simulation of two-dimensional extended materials challenging, and we contrast their resulting high-harmonic emission with more widely studied one-dimensional analogues. As well as considering the photo-induced breakdown of the Mott insulating state and magnetic order, we also resolve the time and ultra-high frequency domains of emission, which are used to characterize both the photo-transition, and the sub-cycle structure of the electron dynamics. This extends simulation capabilities and understanding of the photo-melting of these Mott insulators in two-dimensions, at the frontier of attosecond non-equilibrium science of correlated materials.Comment: 7 pages, 5 figure

High harmonic generation in condensed and engineered materials:introduction

The emerging field of high harmonic generation in condensed matter systems lies at the confluence of strong-field physics, ultrafast optics, and nanotechnology and offers numerous avenues for fundamental research and applications. The goals of this JOSA B feature issue on high harmonic generation in condensed and engineered materials are to facilitate interaction between the different communities and to provide an up-to-date snapshot of the current status of this rapidly developing interdisciplinary field at the frontier of condensed materials and ultrafast physics.</p

Generation of high-order harmonics with tunable photon energy and spectral width using double pulses

This work theoretically investigates high-order harmonic generation in rare gas atoms driven by two temporally delayed ultrashort laser pulses. Apart from their temporal delay, the two pulses are identical. Using a single-atom model of the laser-matter interaction it is shown that the photon energy of the generated harmonics is controllable within the range of one eV -- a bandwidth comparable to the photon energy of the fundamental field -- by varying the time delay between the generating laser pulses. It is also demonstrated that high-order harmonics generated by double pulses have advantageous characteristics, which mimick certain properties of an extreme ultraviolet (XUV) monochromator. With the proposed method, a simpler setup at a much lower cost and comparatively higher spectral yield can be implemented in contrast to other approaches.Comment: 7 pages, 6 figures, after peer-review, corrected typo in author lis

Production et caractérisation d'impulsions attosecondes VUV par génération d'harmoniques d'ordre élevé

La génération d'harmoniques d'ordre élevé (HHG) , qui dans le domaine temporel se traduit par l'émission d'un train d'impulsion VUV attoseconde (1as =10-18s), a connu un grand intérêt scientifique depuis une dizaine d'années. Cette source constitue en effet un bon candidat pour la mise en oeuvre d'expériences pompe sonde visan à observer la dynamique électronique au coeur même des atomes et des molécules. Au CELIA, nous avons implémenté une technique de post-compression qui nous a permis de comprimer nos impulsions laser IR de 40 fs à 9 fs (1fs=10-15s). Ces impulsions sont ensuite utilisées pour confiner la HHG. Etant donné que le processus de HHG est efficace uniquement si les impulsions IR génératrices sont polarisées linéairement, nous avons créé une porte dans le profil temporel de nos impulsions sub-10fs où la polarisation est linéaire pendant une durée inférieure à la durée de l'impulsion IR génératrice. Ceci nous permet de confiner la HHG en dessous d'un demi-cycle optique IR. Cette technique de porte d'ellipticité, complètement caractérisée dans cette thèse, nous a permis de confiner la HHG jusqu'à l'émission d'une à deux impulsions attosecondes. Afin de caractériser le profil temporel au train d'impulsions attosecondes, nous avons également implémenté un interféromètre à deux couleurs qui nous a permit de mesurer la phase harmonique et de reconstruire nos trains d'impulsions attosecondes.BORDEAUX1-BU Sciences-Talence (335222101) / SudocSudocFranceF

Attosecond physics: attosecond measurements and control of physical systems

Attophysics is an emerging field in physics devoted to the study and characterization of matter dynamics in the sub-femtosecond time scale. This book gives coverage of a broad set of selected topics in this field, exciting by their novelty and their potential impact. The book is written review-like. It also includes fundamental chapters as introduction to the field for non-specialist physicists. The book is structured in four sections: basics, attosecond pulse technology, applications to measurements and control of physical processes and future perspectives. It is a valuable reference tool for researchers in the field as well as a concise introduction to non-specialist readers

Attosecond pulses generation with an ellipticity-modulated laser pulse

International audienceAttosecond pulse emission using a laser field with time-dependent ellipticity is studied experimentally and theoretically. Our theoretical approach is validated by comparison with experimental VUV spectra. We show in calculations that the VUV emission can be confined into a narrow temporal window in which the fundamental polarization is quasi-linear. We find an analytical equation describing the duration of this window and compare it with numerical results. The requirements for the fundamental field that are necessary to confine this emission to a single attosecond pulse generation are formulated

Attosecond pulses generation with an ellipticity-modulated laser pulse

Attosecond pulse emission using a laser field with time-dependent ellipticity is studied experimentally and theoretically. Our theoretical approach is validated by comparison with experimental VUV spectra. We show in calculations that the VUV emission can be confined into a narrow temporal window in which the fundamental polarization is quasi-linear. We find an analytical equation describing the duration of this window and compare it with numerical results. The requirements for the fundamental field that are necessary to confine this emission to a single attosecond pulse generation are formulated