Inverse Design of Polaritonic Devices

TL;DR

This paper introduces a differentiable simulation-based inverse design method for creating complex polaritonic devices with tailored functionalities, using topology optimization to engineer potential landscapes for polariton condensates.

Contribution

It presents a novel inverse design approach combining differentiable FDTD simulations and topology optimization for polaritonic devices, enabling complex functionalities with fabrication constraints.

Findings

Successfully designed flat-top polariton structures

Created a polariton-focused metalens

Engineered a nonlinear polaritonic isolator

Abstract

Polaritons, arising from the strong coupling between excitons and photons within microcavities, hold promise for optoelectronic and all-optical devices. They have found applications in various domains, including low-threshold lasers and quantum information processing. To realize complex functionalities, non-intuitive designs for polaritonic devices are required. In this contribution, we use finite-difference time-domain simulations of the dissipative Gross-Pitaevskii equation, written in a differentiable manner, and combine it with an adjoint formulation. Such a method allows us to use topology optimization to engineer the potential landscape experienced by polariton condensates to tailor its characteristics on demand. The potential directly translates to a blueprint for a functional device, and various fabrication and optical control techniques can experimentally realize it. We inverse-design a selection of polaritonic devices, i.e., a structure that spatially shapes the polaritons into a flat-top distribution, a metalens that focuses a polariton, and a nonlinearly activated isolator. The functionalities are preserved when employing realistic fabrication constraints such as minimum feature size and discretization of the potential. Our results demonstrate the utility of inverse design techniques for polaritonic devices, providing a stepping stone toward future research in optimizing systems with complex light-matter interactions.