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