arXiv subjects

Claire M. Cisowski

Publications and source records attributed to Claire M. Cisowski.

4 recordsLinked to original sources

arXiv2024

Algorithmic Discovery of Casimir-Polder forces: Repulsion in the Ground State

We present a general-purpose algorithm for automatic production of a structure that induces a desired Casimir-Polder force. As a demonstration of the capability and wide applicability of the method, we use it to develop a geometry that leads to a repulsive Casimir-Polder force on a ground-state atom. The results turn out to be reminiscent of the ring-like geometries previously used to induce repulsion, but with some new features and -- importantly -- discovered completely independently of any input from the user. This represents a powerful new paradigm in the study of atom-surface forces -- instead of the user testing various geometries against a desired figure of merit, the goal can be specified and then an appropriate geometry created automatically.

quant-ph↗

arXiv2024

Towards nanophotonic optical isolation via inverse design of energy transfer in non-reciprocal media

In this work we generalise the adjoint method of inverse design to nonreciprocal media. As a test case, we use three-dimensional topology optimization via the level-set method to optimise one-way energy transfer for point-like source and observation points. To achieve this we introduce a suite of tools, chiefly what we term the `Faraday-adjoint' method which allows for efficient shape optimization in the presence of magneto-optical media. We carry out an optimization based on a very general equation that we derive for energy transfer in a nonreciprocal medium, and link finite-different time-domain numerics to analytics via a modified Born series generalised to a tensor permittivity. This work represents a stepping stone towards practical nanophotonic optical isolation, often regarded as the `holy grail' of integrated photonics.

physics.optics↗

arXiv2022

Single-shot characterization of vector beams by generalized measurements

Vector vortex beams, featuring independent spatial modes in orthogonal polarization components, offer an increase in information density for emerging applications in both classical and quantum communication technology. Recent advances in optical instrumentation have led to the ability of generating and manipulating such beams. Their tomography is generally accomplished by projection measurements to identify polarization as well as spatial modes. In this paper we demonstrate spatially resolved generalized measurements of arbitrary vector vortex beams. We perform positive operator valued measurements (POVMs) in an interferometric setup that characterizes the vector light mode in a single-shot. This offers superior data acquisition speed compared to conventional Stokes tomography techniques, with potential benefits for communication protocols as well as dynamic polarization microscopy of materials.

physics.optics↗

arXiv2019

Twisted Light and the mirage effect

We study the transformation of an OAM-carrying beam propagating through a vertical gradient of refractive index present in a water-ethanol column. Proper liquid mixing and incidence conditions upon the solution cause the beam to undergo a mirror inversion along the vertical direction, forming an inferior mirage. This path reverses the handedness of the beam and unlike mirror inversion witnessed at sharp interfaces, mirror inversion occurs smoothly and topological charge inversion is accompanied by astigmatic changes. It is also possible to obtain, at the exit of the solution, a beam that has been partially inverted, thus presents spatially varying orbital fluxes.

physics.optics↗