Measurement and simulation of atomic motion in nanoscale optical trapping potentials

Abstract

Atoms trapped in the evanescent field around a nanofiber experience strong coupling to the light guided in the fiber mode. However, due to the intrinsically strong positional dependence of the coupling, thermal motion of the ensemble limits the use of nanofiber trapped atoms for some quantum tasks. We investigate the thermal dynamics of such an ensemble by using short light pulses to make a spatially inhomogeneous population transfer between atomic states. As we monitor the wave packet of atoms created by this scheme, we find a damped oscillatory behavior which we attribute to sloshing and dispersion of the atoms. Oscillation frequencies range around 100 kHz, and motional dephasing between atoms happens on a timescale of 10 µs. Comparison to Monte Carlo simulations of an ensemble of 1000 classical particles yields reasonable agreement for simulated ensemble temperatures between 25 µK and 40 µK.

Observation of oscillatory Raman gain associated with two-photon Rabi oscillations of nanofiber-coupled atoms

“…In spite of the close vicinity of the nanofiber surface, ground-state decoherence times on the order of milliseconds have been experimentally demonstrated for nanofiber-coupled atoms [14]. Experiments employing a Λ-type level structure in this setting include, e.g., EIT-based light storage [15,16], Raman cooling [17,18], generation of single collective excitations [19], probing of the in-trap atomic motion [20], and non-reciprocal Raman amplification [21].…”

A Versatile Quantum Simulator for Coupled Oscillators Using a 1D Chain of Atoms Trapped near an Optical Nanofiber

“…Once trapped, the atoms interact with the evanescent field of light modes propagating within the fiber [5], exchanging energy and momentum. Thus, the light strongly influences the atomic motion in the trap which in turn modifies the light propagation [7][8][9][10]. As photons within the fiber propagate over practically infinite distances, they collectively couple to all atoms, which induces all-to-all long-range interactions [11].…”

A versatile quantum simulator for coupled oscillators using a 1D chain of atoms trapped near an optical nanofiber

“…Once trapped, the atoms interact with the evanescent field of light modes propagating within the fiber [5] exchanging energy and momentum. Thus the light strongly influences the atomic motion in the trap which in turn modifies the light propagation [6,7,8,9]. As photons within the fiber propagate over practically infinite distances they collectively couple to all atoms, which induces all-to-all long-range interactions [10].…”