E. Gallardo

Single photon emission and quantum ring-cavity coupling in InAs/GaAs quantum rings

Different InAs/GaAs quantum rings embedded in a photonic crystal microcavity are studied by quantum correlation measurements. Single photon emission, with g (2) (0) values around 0.3, is demonstrated for a quantum ring not coupled to the microcavity. Characteristic rise-times are found to be longer for excitons than for biexcitons, resulting in the time asymmetry of the exciton-biexciton cross-correlation. No antibunching is observed in another quantum ring weakly coupled to the microcavity.

Microcavity‐Mediated Coupling of Two Distant InAs/GaAs Quantum Dots

We demonstrate the effective coupling between two distant quantum dots embedded in a photonic crystal microcavity. Time‐resolved measurements reveal the simultaneous coupling of both quantum dots to the cavity mode by the Purcell effect. The cavity mediates an interaction between the quantum dots which is evidenced by the increase in the emission intensity of each dot upon the resonant excitation at the excited state of the other one. A linear polarization rotation is observed in one of the dots when the detuning from the cavity mode is varied, which is explained in terms of the hybridization of the quantum dot states and the cavity mode.

Dynamics of InP/(Ga,In)P quantum‐dot single‐photon emitters

The dynamics of single photon emitters based on InP/(Ga,In)P quantum dots (QDs) has been studied by time‐resolved photo luminescence (TRPL) and photon correlation spectroscopy (PCS) up to 50 K. The increase of temperature produces marked effects on the exciton photoluminescence (PL) decay time (τX) and on the anti‐bunching time (τR) in the second order photon correlation function. Both times are found to depend on the QD size. A competition of the thermally activated Dark‐to‐Bright (D→B) exciton transition and the thermal excitation of the carriers to‐ and from the QD give a good qualitative understanding of the observed results. Resonant excitation at the QD p‐states produces a marked decrease of τR together with the appearance of time bunching in a longer time scale.