Microtoroidal cavity QED with fiber overcoupling and strong atom-field coupling: A single-atom quantum switch for coherent light fields

Abstract

We propose a scheme for single-atom, quantum control of the direction of propagation of a coherent field incident, via a tapered fiber, upon a microtoroidal whispering-gallery-mode (WGM) resonator. The scheme involves overcoupling of the fiber-taper to the resonator and strong coupling of an atom to the evanescent field of the WGM, i.e., an atom-field coupling that exceeds the total WGM linewidth. In contrast to previous, related schemes that operate in the bad-cavity regime, the proposed scheme can operate effectively with much stronger incident fields, while also preserving their coherent nature. It can also serve to prepare an entangled state of the atom and coherent optical pulses propagating in opposite directions along the fiber. We evaluate the fidelity of preparation of such a state taking into account absorption and atomic spontaneous emission and demonstrate that high fidelities should be possible with realistic parameters.

Ultrastrong coupling in single plexcitonic nanocubes

“…Although the antenna and face modes overlap spatially and spectrally, such that the branches F and A′ seem unlikely to arise separately from the two modes, the nonidentical distributions of hot spots from the two modes in fact enable the distinguishable strong coupling between the emitters and different cavity modes (see Supplementary Section S4). This is drastically different from the case where indistinguishable emitters are coupled to two cavity modes, resulting in only three branches [48].…”

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On‐chip, dynamic, and cryogenic temperature monitoring via PDMS micro‐bead coatings

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“…The small mode volume, localized to the surface, of optical WGM resonators allows for considerable interaction with surrounding environment, and their intrinsically high‐quality ( Q ) factor enables WGM‐based sensors to exhibit extremely high‐resolution . WGM resonators have found use in microlasers, quantum electrodynamics, optical signal manipulation, etc. In particular, optical WGM sensors are being actively studied in a number of different detection and measurement applications.…”