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