18 research outputs found
Frequency cavity pulling induced by a single semiconductor quantum dot
We investigate the emission properties of a single semiconductor quantum dot
deterministically coupled to a confined optical mode in the weak coupling
regime. A strong pulling, broadening and narrowing of the cavity mode emission
is evidenced when changing the spectral detuning between the emitter and the
cavity. These features are theoretically accounted for by considering the
phonon assisted emission of the quantum dot transition. These observations
highlight a new situation for cavity quantum electrodynamics involving
spectrally broad emitters
Energy-efficient quantum non-demolition measurement with a spin-photon interface
Spin-photon interfaces (SPIs) are key devices of quantum technologies, aimed
at coherently transferring quantum information between spin qubits and
propagating pulses of polarized light. We study the potential of a SPI for
quantum non demolition (QND) measurements of a spin state. After being
initialized and scattered by the SPI, the state of a light pulse depends on the
spin state. It thus plays the role of a pointer state, information being
encoded in the light's temporal and polarization degrees of freedom. Building
on the fully Hamiltonian resolution of the spin-light dynamics, we show that
quantum superpositions of zero and single photon states outperform coherent
pulses of light, producing pointer states which are more distinguishable with
the same photon budget. The energetic advantage provided by quantum pulses over
coherent ones is maintained when information on the spin state is extracted at
the classical level by performing projective measurements on the light pulses.
The proposed schemes are robust against imperfections in state of the art
semi-conducting devices.Comment: Accepted for publication in Quantu
Sources semiconductrices de photons jumeaux
PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF
Quantum stabilization of a single-photon emitter in a coupled microcavity-- half-cavity system Experimental verification of quantum transformation between photon and electron spin View project Terahertz Nondestructive Evaluation of Fiber-reinforced Composites View project
International audienceWe analyze the quantum dynamics of a two-level emitter in a resonant microcavity with optical feedback provided by a distant mirror (i.e., a half-cavity) with a focus on stabilizing the emitter-microcavity subsystem. Our treatment is fully carried out in the framework of cavity quantum electrodynamics. Specifically, we focus on the dynamics of a perturbed dark state of the emitter to ascertain its stability (existence of time oscillatory solutions around the candidate state) or lack thereof. In particular, we find conditions under which multiple feedback modes of the half cavity contribute to the stability, showing certain analogies with the Lang-Kobayashi equations, which describe a laser diode subject to classical optical feedback