Towards Atom Assembly on Nanophotonic Structures with Optical Tweezers

Abstract

The integration of atomic physics and nanophotonics combines the best of two worlds. With atoms as the naturally existing qubits and nanophotonic devices as the engineered interaction medium, new frontiers can be explored for building novel quantum optical circuits for non-conventional quantum optics and exotic quantum many-body physics, as well as potentially serving as a fundamental building block for quantum computation and communication with neutral atoms. While important experimental milestones towards this goal have been reached, a grand challenge for experiments in this new field is the loading and trapping of atomic arrays with high fractional filling near complex nanophotonic structures. In this thesis, we have proposed a novel protocol for atom assembly on nanophotonic structures by integrating optical tweezer arrays and photonic crystal waveguides. This research is inspired by recent exciting progress in free-space atom assembly. However, different from the free-space counterpart, our new proposal should enable subwavelength atom arrays with complex patterns defined by precision nanofabrication. To demonstrate the basic principles behind this new proposal, we have designed and built an advanced apparatus with compact footprint that overcomes several significant experimental barriers in previous experiments. To achieve efficient atom delivery and assembly of arrays for more complex nanostructures, we have proposed a novel direct delivery scheme with optical tweezers by exploiting the rapid spatial variation of the Gouy phase of radial Laguerre-Gauss beams. With reduced dimension in the axial direction, the optical tweezer formed by supposed Laguerre-Gauss beams may find important applications in the communities of general atomic physics and super-resolution imaging. Finally, we have investigated the optomechanical properties of our nanophotonic devices for trapping atoms and evaluated potential heating mechanisms for trapped atoms. The studies presented in this thesis should provide important guidance to future atom-nanophotonic experiments.