We demonstrate theoretically that it is possible to use Rabi oscillations to
coherently control the electron tunneling in an asymmetric double quantum dot
system, a quantum dot molecule. By applying an optical pump pulse we can excite
an electron in one of the dots, which can in turn tunnel to the second dot, as
controlled by an external voltage. Varying the intensity of the pulse one can
suppress or enhance the tunneling between the dots for given level resonance
conditions. This approach allows substantial flexibility in the control of the
quantum mechanical state of the system.Comment: 4 pages, 5 figures, to appear in PR
We study the optical emission from single semiconductor quantum dots coupled to the optical modes of photonic crystal nanocavities. For dots that are both spectrally and spatially coupled, auto-correlation measurements reveal efficient single photon generation, with a drastically reduced lifetime due to the Purcell-effect. However, the multi-photon emission probability is enhanced compared to the same QD transition when it is detuned from the cavity mode by controlled N2deposition. This indicates the presence of an emission background that is shown to be related to the dot using photon cross-correlation spectroscopy. Photon temporal correlations persist even for large spectral detunings beyond ∆λ ∼ −10 nm, excluding the intrinsic QD continuum and phonon mediated processes as being responsible for the cavity mode emission background. We propose a mechanism based on photon induced shake up processes in the charged quantum dots, enhanced by the optical cavity.
We present a combined experimental and theoretical study of the emission spectrum of zero dimensional nanocavity polaritons in electrically tunable single dot nanocavities. Such devices allow us to vary the dot-cavity detuning in situ and probe the emission spectrum under well-controlled conditions of lattice temperature and incoherent excitation level. Our results show that the observation of a double peak in the emission spectrum is not an unequivocal signature of strong coupling. Moreover, by comparing our results with theory, we extract the effective vacuum Rabi splitting, the pure dephasing rate, and their dependence on the incoherent optical pumping power and lattice temperature. Our study highlights how coupling to the lattice and dynamical fluctuations in the solid-state environment influence the coherence properties of quantum dot microcavity polaritons and, sometimes, may mask the occurrence of strong coupling.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.