arXiv subjects

Benjamin Dawson

Publications and source records attributed to Benjamin Dawson.

4 recordsLinked to original sources

arXiv2023

Mirror-mediated ultralong-range atomic dipole-dipole interactions

In three dimensions, dipole-dipole interactions which alter atomic level shifts and spontaneous decay rates only persist over distances comparable to the wavelength of the emitted light. In this paper we show that it is possible to significantly extend the range of these interactions with the help of a partially transparent asymmetric mirror interface. Suppose two two-level atoms are placed on opposite sides of the interface, each at the position of the mirror image of the other. In this case, their emitted light interferes almost exactly as it would when the atoms are right next to each other. Hence their dipole-dipole interaction assumes an additional maximum, even when the actual distance of the atoms is several orders of magnitude larger than the transition wavelength. Although the resulting ultralong-range interactions are in general relatively weak, we expect them to find applications in quantum technology, like non-invasive quantum sensing.

quant-ph↗

arXiv2022

Remote non-invasive Fabry-Perot cavity spectroscopy for label-free sensing

One way of optically monitoring molecule concentrations is to utilise the high sensitivity of the transmission and reflection rates of Fabry-Perot cavities to changes of their optical properties. Up to now, intrinsic and extrinsic Fabry-Perot cavity sensors have been considered with analytes either being placed inside the resonator or coupled to evanescent fields on the outside. Here we show that Fabry-Perot cavities can also be used to monitor molecule concentrations non-invasively and remotely, since the reflection of light from the target molecules back into the Fabry-Perot cavity adds upwards peaks to the minima of its overall reflection rate. Detecting the amplitude of these peaks reveals information about molecule concentrations. By using an array of optical cavities, a wide range of frequencies can be probed at once and a unique optical fingerprint can be obtained.

physics.optics↗

arXiv2021

The quantum optics of asymmetric mirrors with coherent light absorption

The local observables of the quantised electromagnetic field near a mirror-coated interface depend strongly on the properties of the media on {\em both} sides. In macroscopic quantum electrodynamics, this fact is taken into account with the help of optical Green's functions which correlate the position of an observer with all other spatial positions and photon frequencies. Here we present an alternative, more intuitive approach and obtain the local field observables with the help of a quantum mirror image detector method [Furtak-Wells et al., Phys. Rev. A 97, 043827 (2018)]. In order to correctly normalise electric field operators, we demand that spontaneous atomic decay rates simplify to their respective free space values far away from the reflecting surface. Our approach is interesting, since mirror-coated interfaces constitute a common basic building block for quantum photonic devices.

quant-ph↗

arXiv2020

Spontaneous emission of atomic dipoles near two-sided semi-transparent mirrors

Atom-field interactions near optical interfaces have a wide range of applications in quantum technology. Motivated by this, this paper revisits the spontaneous emission of atomic dipoles in the presence of a two sided semi-transparent mirror. First we review the main properties of the quantised electromagnetic field near a semi-transparent mirror. To do so, we employ a quantum mirror image detector method which maps the experimental setup which we consider here onto analogous free space scenarios. We emphasise that the local density of states of the electromagnetic field depends on the reflection rates of both sides of the mirror surface. Hence it is not surprising that also the spontaneous decay rate of an atomic dipole in front of a semi-transparent mirror depends on both reflectance rates. Although the effect which we describe here only holds for relatively short atom-mirror distances, it can aid the design of novel photonics devices.

quant-ph↗