Probing electron-phonon interaction through two-photon interference in resonantly driven semiconductor quantum dots

We investigate the temperature dependence of photon coherence properties through two-photon interference (TPI) measurements from a single quantum dot (QD) under resonant excitation. We show that the loss of indistinguishability is related only to the electron-phonon coupling and is not affected by spectral diffusion. Through these measurements and a complementary microscopic theory, we identify two independent separate decoherence processes, both of which are associated with phonons. Below 10 K, we find that the relaxation of the vibrational lattice is the dominant contribution to the loss of TPI visibility. This process is non-Markovian in nature and corresponds to real phonon transitions resulting in a broad phonon sideband in the QD emission spectra. Above 10 K, virtual phonon transitions to higher lying excited states in the QD become the dominant dephasing mechanism, this leads to a broadening of the zero phonon line, and a corresponding rapid decay in the visibility. The microscopic theory we develop provides analytic expressions for the dephasing rates for both virtual phonon scattering and non-Markovian lattice relaxation

Chemotherapy is not needed when complete evacuation of gestational choriocarcinoma leads to hCG normalisation.

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Synthesis, characterisation and aqueous behaviour of a one-ended perfluorocarbon-modified poly(ethylene glycol)

International audienceEstablishing structure–properties relationships for an associative polymer requires a precise knowledge of its structure. In previous works, we studied water-soluble telechelic perfluorocarbon (C8F17) derivatives of poly(ethylene glycol)s. They exhibit stronger hydrophobic intermolecular associations than the corresponding hydrocarbon derivatives (C8H17). We now report the synthesis and study of one-ended perfluorocarbon derivative of poly(ethylene glycol). The composition and structure of this polymer were elucidated before analysing its behaviour in aqueous solution by viscosimetry and 19F NMR. The synthesis procedure allows us to reach total grafting. This polymer presents a micellar behaviour above 2×10−4 g/ml and an associative behaviour above 10−3 g/ml

Luciana Gentilli y Renata Londero, eds., «Sátira y encomiástica en las artes y letras del siglo XVII español»

Recesione del volume «Sátira y encomiástica en las artes y letras del siglo XVII español

Optical Probing of Rayleigh Wave Driven Magnetoacoustic Resonance

International audienceThe resonant interaction of electrically excited traveling surface acoustic waves and magnetization has hitherto been probed through the acoustic component. In this work we investigated it using time-resolved magneto-optical detection of magnetization dynamics. To that end, we develop an experimental scheme where laser pulses are used both to generate the acoustic wave frequency and to probe magnetization dynamics, thus ensuring perfect phase locking. The light-polarization dependence of the signal enables us to disentangle elasto-optical and magneto-optical contributions and to obtain the in-plane and out-of-plane components of the magnetization dynamics. Magnetization precession is proven to be driven solely by the acoustic wave. Its amplitude is shown to resonate at the same field at which we detect piezoelectrically the resonant attenuation of the acoustic wave, clearly evidencing the magnetoacoustic resonance with high sensitivity

Optical Probing of Wave Driven Magneto-acoustic Resonance

Publiée sous le titre Optical Probing of Rayleigh Wave Driven Magneto-acoustic ResonanceInternational audienceThe resonant interaction of electrically excited traveling surface acoustic waves and magnetization has hitherto been probed through the acoustic component. In this work we investigated it using time-resolved magneto-optical detection of magnetization dynamics. To that end, we develop an experimental scheme where laser pulses are used both to generate the acoustic wave frequency and to probe magnetization dynamics, thus ensuring perfect phase locking. The light-polarization dependence of the signal enables us to disentangle elasto-optical and magneto-optical contributions and to obtain the in-plane and out-of-plane components of the magnetization dynamics. Magnetization precession is proven to be driven solely by the acoustic wave. Its amplitude is shown to resonate at the same field at which we detect piezoelectrically the resonant attenuation of the acoustic wave, clearly evidencing the magnetoacoustic resonance with high sensitivity