This paper reports on the excitation of surface plasmons on gold-coated nanofibre tips by side-illumination with a laser beam and the coupling of the surface plasmons to the optical fiber. The measurements show a strong dependence of the coupling eff
iciency on the incidence angle with a maximum coupling efficiency on the order of few percent. Moreover, the fibre tip was used as scanning probe device for measuring the beam waist of a focussed laser beam. This work is motivated by the goal to use such plasmonic nanofibre tips in quantum optics experiments with cold atoms.
Understanding superfluidity with higher order partial waves is crucial for the understanding of high-$T_c$ superconductivity. For the realization of a superfluid with anisotropic order parameter, spin-polarized fermionic lithium atoms with strong p-w
ave interaction are the most promising candidates to date. We apply rf-spectroscopy techniques that do not suffer from severe final-state effects cite{Perali08} with the goal to perform photoemission spectroscopy on a strongly interacting p-wave Fermi gas similar to that recently applied for s-wave interactions cite{Stewart08}. Radiofrequency spectra of both quasibound p-wave molecules and free atoms in the vicinity of the p-wave Feshbach resonance located at 159.15,G cite{Schunck05} are presented. The observed relative tunings of the molecular and atomic signals in the spectra with magnetic field confirm earlier measurements realized with direct rf-association cite{Fuchs08}. Furthermore, evidence of bound molecule production using adiabatic ramps is shown. A scheme to observe anisotropic superfluid gaps, the most direct proof of p-wave superfluidity, with 1d-optical lattices is proposed.
We report on the observation of five Feshbach resonances in collisions between ultracold $^7$Li and $^{87}$Rb atoms in the absolute ground state mixture where both species are in their $|f,m_f>=|1,1>$ hyperfine states. The resonances appear as trap l
osses for the $^7$Li cloud induced by inelastic heteronuclear three-body collisions. The magnetic field values where they occur are important quantities for an accurate determination of the interspecies interaction potentials. Results of coupled channels calculations based on the observed resonances are presented and refined potential parameters are given. A very broad Feshbach resonance centered around 649 G should allow for fine tuning of the interaction strength in future experiments.
We report on the observation of two Feshbach resonances in collisions between ultracold $^6$Li and $^{87}$Rb atoms in their respective hyperfine ground states $|F,m_F>=|1/2,1/2>$ and $|1,1>$. The resonances show up as trap losses for the $^6$Li cloud
induced by inelastic Li-Rb-Rb three-body collisions. The magnetic field values where they occur represent important benchmarks for an accurate determination of the interspecies interaction potentials. A broad Feshbach resonance located at 1066.92 G opens interesting prospects for the creation of ultracold heteronuclear molecules. We furthermore observe a strong enhancement of the narrow p-wave Feshbach resonance in collisions of $^6$Li atoms at 158.55 G in the presence of a dense $^{87}$Rb cloud. The effect of the $^{87}$Rb cloud is to introduce Li-Li-Rb three-body collisions occurring at a higher rate than Li-Li-Li collisions.
