Erlangen 2018 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 57: Ultracold Atoms I (joint session Q/A)

Q 57.3: Talk

Thursday, March 8, 2018, 11:00–11:15, K 1.022

Ground state cooling of atoms 300 nm away from a hot surface — •Yijian Meng, Alexandre Dareau, Philipp Schneeweiss, and Arno Rauschenbeutel — VCQ, TU Wien – Atominstitut, Stadionallee 2, 1020 Wien, Austria

Cold atoms coupled to light guided in nanophotonic structures constitute a powerful research platform, e.g., for probing surface forces, the study of light-induced self-organization, as well as quantum networking. The strong spatial confinement of the optical trapping fields in nanophotonic systems gives rise to significant fictitious magnetic field gradients. These can be used to perform degenerate Raman cooling (DRC), which has been pioneered in optical lattices [1].

Here, we implement DRC of atoms in a nanofiber-based optical trap [2]. Remarkably, this scheme only requires a single fiber-guided light field, which provides three-dimensional cooling. We show that continuously applying such cooling extends the lifetime of atoms in the trap by one order of magnitude. Using fluorescence spectroscopy [3], we precisely measure the temperature of the atoms. We find that they can be cooled close to the motional ground state despite the atoms being less than 300 nm away from the hot fiber surface. This achievement sets an excellent starting point for further experiments, for example, the investigation of heat transfer at the nanoscale using quantum probes.
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