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

Experimental realization of a coherent Raman comb

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Strong phase-locking in quantum seeded of Raman comb

International audienceWe demonstrate strong and stable phase-locking between the pump and the quantum generated Stokes/anti-Stokes spectral-pair in a comb generated in the regime of a single spatiotemporal coherent mode transient stimulated Raman scattering in H2-filled HCPCF

Increasing photon-pairs source brightness based on inhibitedcoupling hollow-core fiber

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Réalisation d'une mer de Fermi dipolaire d'atomes de chrome

Il s'agit de la première réalisation mondiale d'un gaz dégénéré dipolaire avec l'isotope fermionique du chrome.International audienceWe report on the production of a degenerate Fermi gas of 53Cr atoms, polarized in the stateF=9/2, mF = −9/2, by sympathetic cooling with bosonic S=3, mS = −3 52Cr atoms. We load inan optical dipole trap 30 000 53Cr atoms with one million 52Cr atoms. Despite this initial small numberof fermionic atoms, we reach a final temperature of T ≃ 0.6 × Tf (Fermi temperature), with upto thousand 53Cr atoms. This surprisingly efficient evaporation stems from an inter-isotope scatteringlength |aBF | = 85(±10) aB (Bohr radius) which is small enough to reduce evaporative losses of thefermionic isotope, but large enough to insure thermalization

High brightness single photon source at the telecom wavelength based on inhibited-coupling hollow-core fiber

International audienceWe report on a Raman-free heralded single-photon source based on xenon-filled hollowcore fiber pumped with GHz-repetition rate femtosecond laser. The measured brightness of 720 kHz is one order of magnitude improvement over our previous demonstration