Optimization of metasurfaces for lasing with symmetry constraints on the modes

TL;DR

This paper introduces a symmetry-based multi-objective optimization method for designing active metasurfaces, enabling improved control over mode properties for enhanced lasing performance.

Contribution

It presents a novel symmetry projection operator technique for optimizing metasurface eigenmodes, addressing conflicting design requirements in active metasurface systems.

Findings

Optimized lasing metasurface for high directionality

Enhanced mode control with symmetry-based optimization

Reduced lasing threshold and improved emission properties

Abstract

The development of active metasurface systems, such as lasing metasurfaces, requires the optimization of multiple modes at the absorption and lasing wavelength bands, including their quality factor, mode profile and angular dispersion. Often, these requirements are contradictory and impossible to obtain with conventional design techniques. Importantly, the properties of the eigenmodes of a metasurface are directly linked to their symmetry, which offers an opportunity to explore mode symmetry as an objective in optimization routines for active metasurface design. Here, we propose and numerically demonstrate a novel multi-objective optimization technique based on symmetry projection operators to quantify the symmetry of the metasurface eigenmodes. We present, as an example, the optimization of a lasing metasurface based on up-converting nano-particles. Our technique allows us to optimize the absorption mode dispersion, as well as the directionality of the lasing emission and therefore offers advantages for novel lasing systems with high directionality and low lasing threshold.