Search results for "Citation"
showing 10 items of 1710 documents
Ultrafast Dynamics of Dansylated POPAM Dendrimers and Energy Transfer in their Dye Complexes
2009
We have studied internal dynamics of dansylated poly(propyleneamine) dendrimers of different generations in solution and excitation energy transfer from dansyl chromophores to xanthene dyes that form van der Waals complexes with the dendrimers
Energy transfer to xanthene dyes in dansylated POPAM dendrimers
2011
Abstract Excitation energy transfer (EET) in host–guest complexes of dansylated POPAM dendrimers and xanthene dyes have been studied by transient absorption spectroscopy. EET from dansyl periphery to guests: rose bengal, eosin, or fluorescein, showed non-exponential behaviour as a result of distribution of donor–acceptor distances. Time constants range from 100 fs to 8 ps, independent of the dye and the dendrimer generation. Experiments suggested that in dendrimers binding more than one guest, EET among the guests becomes effective. Guest–host and guest–guest interactions induce non-radiative relaxation channels making excitation decays of the guests clearly faster in complexes than in solu…
Acoustic vibrations of metal nanoparticles: high order radial mode detection
2004
The vibrational radial modes of silver nanospheres embedded in a glass matrix are investigated using a high sensitivity femtosecond pump-probe technique. The results yield evidence for coherent launching of the fundamental and higher order radial modes in agreement with a sphere dilation mediated excitation model. The results are consistent with low-frequency Raman scattering experiments.
Hyperfine Paschen-Back regime realized in Rb nanocell
2012
A simple and efficient scheme based on one-dimensional nanometric thin cell filled with Rb and strong permanent ring magnets allowed direct observation of hyperfine Paschen-Back regime on D1 line in 0.5 - 0.7 T magnetic field. Experimental results are perfectly consistent with the theory. In particular, with sigma+ laser excitation, the slopes of B-field dependence of frequency shift for all the 10 individual transitions of 85,87Rb are the same and equal to 18.6 MHz/mT. Possible applications for magnetometry with submicron spatial resolution and tunable atomic frequency references are discussed.
"Safe" Coulomb excitation of 30Mg.
2004
We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient $\gamma$ -spectrometer MINIBALL. Using $^{30}$Mg ions accelerated to an energy of 2.25MeV/u together with a thin $^{nat}$Ni target, Coulomb excitation of the first excited 2+ states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative de-excitation $\gamma$ -ray yields the B(E2; 0$^{+}_{gs} \rightarrow 2^{+}_{1}$) value of $^{30}$Mg was determined to be 241(31)$e^{2}$fm$^{4}$. Our result is lower than values obtained at projectile fragmenttion facilities using the intermediate-ene…
Local detection of the optical magnetic field in the near zone of dielectric samples
2000
International audience; We present a study of the influence of the probe composition on the formation of constant-height photon scanning tunneling microscope images when observing a dielectric sample. Dramatic effects due to the metallization of the tip are presented and discussed in detail. We show how the recorded images can look quite different when the probe is dielectric or coated with gold. Comparison with numerical calculations indicate that the experimental signals are of electric or magnetic nature depending on the composition of the tip. For well-defined conditions, gold-coated tips provide images of the distribution of the magnetic field intensity associated with the optical near…
Dielectric-loaded surface plasmon-polariton waveguides at telecommunication wavelengths: Excitation and characterization
2008
International audience; The excitation and propagation of strongly confined surface plasmon-polariton (SPP) waveguide modes, supported by 500-nm-wide and 550-nm-high dielectric ridges fabricated on smooth gold films, are investigated at telecommunication wavelengths using a scanning near-field optical microscope. Different tapering structures for coupling of SPPs, excited at bare gold surfaces, into dielectric-loaded SPP waveguide (DLSPPW) modes are considered. The DLSPPW mode confinement and propagation loss are characterized. The DLSPPW mode propagation along an S bend having the smallest curvature radius of 2.48 mu m is shown, demonstrating the potential of DLSPPW technology for the real…
Modèles quantiques à deux états avec croisements de niveaux décrits par les fonctions de Heun
2019
The thesis is devoted to the fundamental problem of excitation and manipulation of quantum systems, having discrete energy spectrum, via external laser fields. We examine the semiclassical time- dependent quantum two-state problem, when the external electromagnetic field is resonant or quasi-resonant for some two of many levels of the system. The focus of the thesis is on the analytic description of the non- adiabatic evolution of quantum systems subject to excitation by level-crossing field configurations. In the present thesis we classify the complete set of the semiclassical time-dependent quantum two-state models solvable in terms of the five function of the Heun class.Main results of t…
Revised Analysis of the Structure of the v1 Band of Methane
1983
Abstract The CARS spectrum of the v 1 band of 12 CH 4 at a pressure of 14 mbar was recorded using cw excitation in the cavity of a ring argon ion laser. The analysis of the intensity profile of the obarred spectrum led to the detection of inconsistencies with the hitherto proposed calculated positions of transitions with J = 7 to J = 10 and to a relocation of the corresponding lines.
Discontinuity induced angular distribution of photon plasmon coupling
2011
Metal-dielectric transitions are important structures that can display a host of optical characteristics including excitation of plasmons. Metal-dielectric discontinuities can furthermore support plasmon excitation without a severe condition on the incident angle of the exciting photons. Using a semi-infinite thin gold film, we study surface plasmon (SP) excitation and the associated electromagnetic near-field distribution by recording the resulting plasmon interference patterns. In particular, we measure interference periods involving SPs at the scanable metal/air interface and the buried metal/glass one. Supported by optical near-field simulations and experiments, we demonstrate that the …