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