High-efficiency cold-atom transport into a waveguide trap

Abstract

We have developed and characterized an atom-guiding technique that loads 3 × 10 6 cold rubidium atoms into hollow-core optical fibre, an order-of-magnitude larger than previously reported results. This result was possible because it was guided by a physically realistic simulation that could provide the specifications for loading efficiencies of 3.0 % and a peak optical depth of 600. The simulation further showed that the demonstrated loading efficiency is limited solely by the geometric overlap of the atom cloud and the optical guide beam, and is thus open to further improvement with experimental modification. The experimental arrangement allows observation of the real-time effects of light-assisted cold atom collisions and background gas collisions by tracking the dynamics of the cold atom cloud as it falls into the fibre. The combination of these observations, and physical understanding from the simulation, allows estimation of the limits to loading cold atoms into hollowcore fibres.

Light-shift spectroscopy of optically trapped atomic ensembles

“…In many cases optical dipole traps are used to localise the atomic ensemble in a controllable way. These can be used to hold the atomic sample for a long duration [12,17,18] or to transport the atoms into a confined geometry such as a hollow-core fibre [19][20][21][22][23][24] or near to a structured device such as an atomic chip [25][26][27][28].…”

Transporting Long-Lived Quantum Spin Coherence in a Photonic Crystal Fiber

“…The coherence time of stationary atoms has been demonstrated to few milliseconds [8]. Trapping and guiding of atoms in hollow-core photonic crystal fibres [9][10][11] have been demonstrated over centimeter distances [12][13][14][15][16][17][18][19]; however, the ability to maintain the coherence of quantum superposition states * sylan@ntu.edu.sg over a large distance is still unclear. A moving atom interferometer has been demonstrated inside a hollow-core photonic crystal fibre, but the coherence time was limited by the dephasing caused by the trapping potential to tens of microseconds [16].…”

Unidirectional spin transport of a spin-orbit-coupled atomic matter wave using a moving Dirac δ -potential well

“…Except for this sudden dropping of transporting efficiency, in the figure one also notices a slowly dropping of the total transported atom number as the transporting velocity increases. Mathematically, this is because, for a large value of v, the factor exp [ivx] in equation (13) contributes a fast oscillation, which will reduce the transported matterwave amplitude. Physically, this can be explained by the fact that a faster moving of the potential tends to excite more atoms out of the trapping well.…”