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We study optical field emission from silver nanotips, showing the combined influence of the illumination wavelength and the exact shape of the nanotip on the strong-field response. This is particularly relevant in the case of FIB milled nano tips, where the nanotip fabrication capabilities could become a new ingredient for the study of strong-field physics. The influence of the thermal load on the nanotip and its effect on the emission is studied as well by switching the repetition rate of the laser source from 1 kHz to 62 MHz, showing a clear transition towards the quenching of the strongfield emission.

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Bell's inequality violation experiments are becoming increasingly popular in the practical teaching of undergraduate and master's degree students. Bell's parameter S is obtained from 16 polarization correlation measurements performed on entangled photons pairs. We first report here a detailed analysis of the uncertainty u(S) of Bell's parameter taking into account coincidence count statistics and errors in polarizers' orientation. We show using both computational modeling and experimental measurement that the actual sequence of the polarizer settings has an unexpected and strong influence on the error budget. This result may also be relevant to measurements in other settings in which errors in parameters may have non-random effects in the measurement.

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We report results of experimental investigation of field electron emission from diamond nanoemitters. The measurements were performed with single crystal diamond needles fixed at tungsten tips. The voltage drop along diamond needles during emission was revealed and measured using electron energy spectroscopy. The observed linear dependence of the voltage drop in diamond on voltage applied to the tungsten tip is explained in the frame of a simple macroscopic electrical model combining Poole–Frenkel conduction along the diamond tip and Fowler–Nordheim tunneling at the diamond-vacuum junction. Experimental evidences of electron emission sensitivity to laser illumination are discussed for possible modification of diamond emitter characteristics and voltage drop.

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High-order harmonic generation in polyatomic molecules generally involves multiple channels of ionization. Their relative contribution can be strongly influenced by the presence of resonances, whose assignment remains a major challenge for high-harmonic spectroscopy. Here we present a multi-modal approach for the investigation of unaligned polyatomic molecules, using ​SF6 as an example. We combine methods from extreme-ultraviolet spectroscopy, above-threshold ionization and attosecond metrology. Fragment-resolved above-threshold ionization measurements reveal that strong-field ionization opens at least three channels. A shape resonance in one of them is found to dominate the signal in the 20–26 eV range. This resonance induces a phase jump in the harmonic emission, a switch in the polarization state and different dynamical responses to molecular vibrations. This study demonstrates a method for extending high-harmonic spectroscopy to polyatomic molecules, where complex attosecond dynamics are expected.

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Sujets

Chlorine azide Chirped pulses Photoemission Caractérisation complète Acétylène Rabi oscillations Echantillon multidiffusant Bell's inequality Anharmonicity Photoémission Extreme ultraviolet Rubidium atom Boîte quantique semiconductrice Expérience pompe-sonde 7867Pt Adiabatic rapid passage Azoture de chlore Factorisation 4265Re Emission par champ froid Quantum path interferences 7960Jv C2H2 Pump-probe Velocity map imaging Chirped laser pulses Molecular dynamics Excited states sodium Half revival Femtosecond Ultrashort pulses Femtosecond spectroscopy ELEMENTAL FRACTIONATION ENERGY Coherent pulse propagation Atom-photon collisions ClN3 Génération d'harmoniques d'ordre élevé Pulse shaping Mise en forme d'impulsions ATOMS Cold field emission Number theory Femtosecond pulse CHLORINE AZIDE Femtosecond lasers Spin-orbit precession Expériences pompe-sonde CIN3 Contrôle spatio-temporel Cold Molecules Ultraviolet ALIGNED MOLECULES Femtochemistry Quantum dots Ultrashort lasers Azulene CYCLIC-N-3 Contrôle cohérent Ultrafast nonlinear optics Coherent Transients Caractérisation Femtosecond pulses Dynamique moléculaire XUV Chirp modulation rotational states quantum theory energy level crossing laser beams dissociation Wave packet interferences 4225Ja Time-resolved photoelectron spectroscopy Diamond nanotip Champ fort Optical Parametric Amplifier Coherent transients AOPDF Interférences de chemins quantiques Cold molecules 4230Kq Characterisation CHARGE-TRANSFER Coherent Transient Femtosecond laser Gauss sums Caractérisation spatio-temporelle Attosecond NO2 Transitoires cohérents Oscillations de Rabi Attoseconde Mise en forme d'impulsion Autocorrelation function Factorization Impulsions à dérive de fréquence Quantum state measurement Diffractive optical element Passage adiabatique rapide Femtoseconde Complete characterization Couplage spatio-temporel 4265Ky Coherent control

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