Emission in a Resonator

Romain Coussement, G. Neyens, M. van den Bergh +1 more

Daniel J. Heinzen, James Childs, Michael S. Feld

Recently, we observed enhancement and inhibition of visible spontaneous emission by atoms in a confocal resonator.1 In these experiments, the partial emission rate of the atom into the resonator modes is modified by a factor of 1/(1 − R), where R is the mirror reflectivity. The change in the total spontaneous emission rate is proportional to the solid angle ΔΩ subtended by the mirrors; the change was small (+1.6%, −0.5%) because ΔΩ ≈ 0.04 sr was small. Currently we are conducting experiments in which atoms are placed in a concentric resonator of large solid angle ΔΩ ≈ 3.6 sr and finesse of ~10. We estimate that a 30% decrease and 300% increase should be observable in the total spontaneous emission rate, when the resonator is tuned off or on-resonance, respectively. Results of this new experiment are presented. In addition to studying spontaneous processes, one can also consider the stimulated emission which occurs when a cavity field builds up which contains more than one photon. We have formulated a model which describes both the spontaneous and stimulated emission by the atom into the cavity and clarifies the relationship between enhanced spontaneous emission and stimulated emission.

Daniel J. Heinzen, James Childs, John E. Thomas +1 more

We report the alteration of visible spontaneous emission by atoms coupled to the degenerate modes of a confocal resonator. The partial emission rate into the resonator modes is enhanced by a factor of 19 when the resonator is tuned to the atomic transition frequency and inhibited by a factor of 42 when it is detuned. This results in a fractional increase of 1.6% and decrease of 0.5%, respectively, in the total spontaneous emission rate, which we verify by monitoring changes in the intensity of light emitted out the sides of the resonator as it is tuned.

А. В. Андреев

Hai Son Nguyen, Gregory C. Sallen, Christophe Voisin +3 more

We report on the resonant emission in coherently driven single semiconductor quantum dots. We demonstrate that an ultraweak nonresonant laser acts as an optical gate for the quantum dot resonant response. We show that the gate laser suppresses Coulomb blockade at the origin of a resonant emission quenching, and that the optically gated quantum dots systematically behave as ideal two-level systems in both regimes of coherent and incoherent resonant emission.