Quantum state-controlled directional spontaneous emission of photons into a nanophotonic waveguide.

The spin of light in subwavelength-diameter waveguides can be orthogonal to the propagation direction of the photons because of the strong transverse confinement. This transverse spin changes sign when the direction of propagation is reversed. Using this effect, we demonstrate the directional spontaneous emission of photons by laser-trapped caesium atoms into an optical nanofibre and control their propagation direction by the excited state of the atomic emitters. In particular, we tune the spontaneous emission into the counter-propagating guided modes from symmetric to strongly asymmetric, where more than % of the optical power is launched into one or the other direction. We expect our results to have important implications for research in quantum nanophotonics and for implementations of integrated optical signal processing in the quantum regime.

Coherence properties of nanofiber-trapped cesium atoms.

We experimentally study the ground state coherence properties of cesium atoms in a nanofiber-based two-color dipole trap, localized ∼ 200 nm away from the fiber surface. Using microwave radiation to coherently drive the clock transition, we record Ramsey fringes as well as spin echo signals and infer a reversible dephasing time of T(2)(*) = 0.6 ms and an irreversible dephasing time of T(2)(') = 3.7 ms. By modeling the signals, we find that, for our experimental parameters, T(2)(*) and T(2)(') are limited by the finite initial temperature of the atomic ensemble and the heating rate, respectively. Our results represent a fundamental step towards establishing nanofiber-based traps for cold atoms as a building block in an optical fiber quantum network.

Dispersive optical interface based on nanofiber-trapped atoms.

We dispersively interface an ensemble of 1000 atoms trapped in the evanescent field surrounding a tapered optical nanofiber. This method relies on the azimuthally asymmetric coupling of the ensemble with the evanescent field of an off-resonant probe beam, transmitted through the nanofiber. The resulting birefringence and dispersion are significant; we observe a phase shift per atom of ∼1 mrad at a detuning of 6 times the natural linewidth, corresponding to an effective resonant optical density per atom of 0.027. Moreover, we utilize this strong dispersion to nondestructively determine the number of atoms.

Carbamazepine toxicity precipitated by intravenous erythromycin.

The ability of erythromycin to inhibit the hepatic metabolism of carbamazepine causes carbamazepine toxicity. The severity of this drug interaction has been proposed to be related to the dose of erythromycin. The introduction of oral erythromycin produces a two- to fourfold increase in the carbamazepine serum concentration and the resultant toxic manifestations. Carbamazepine toxicity and a more marked increase in carbamazepine serum concentration were observed in a patient treated with intravenous erythromycin.

Syndrome of inappropriate antidiuretic hormone with imipramine.

Among the various medications that have been associated with the development of syndrome of inappropriate antidiuretic hormone secretion (SIADH) are the tricyclic antidepressants. A 69-year-old man admitted for treatment of a depressive disorder that had not responded to trazodone was prescribed imipramine. Twenty-two days after initiation of therapy, the patient developed hyponatremia. The patient also had depressed serum osmolality and elevated urine sodium concentrations consistent with SIADH. With the discontinuation of imipramine, fluid restriction, and several doses of furosemide, normal serum sodium concentrations were attained. As antidepressant therapy was indicated, doxepin was selected. The patient maintained normal electrolyte values and water balance over the next two months of follow-up. No reports of doxepin-related SIADH were found in the literature; therefore, this agent may be considered as an alternative therapy in patients developing SIADH during antidepressant drug therapy.