Adding SALT to Coupled Microcavities: the making of active photonic molecule lasers

TL;DR

This paper combines SALT and Lorenz-Mie theory to analyze and enhance the lasing properties of photonic molecule lasers, enabling better control over their spectral and emission characteristics.

Contribution

It introduces a combined theoretical framework using SALT and Lorenz-Mie theory for active photonic molecules, advancing the understanding of their lasing behavior.

Findings

Enhanced control over lasing thresholds and emission directionality.

Accurate modeling of active photonic molecule resonances.

Potential for designing ultra-low threshold microlasers.

Abstract

A large body of work has accumulated over the years in the study of the optical properties of single and coupled microcavities for a variety of applications, ranging from filters to sensors and lasers. The focus has been mostly on the geometry of individual resonators and/or on their combination in arrangements often referred to as photonic molecules (PMs). Our primary concern will be the lasing properties of PMs as ideal candidates for the fabrication of integrated microlasers, photonic molecule lasers. Whereas most calculations on PM lasers have been based on cold-cavity (passive) modes, i.e. quasi-bound states, a recently formulated steady-state ab initio laser theory (SALT) offers the possibility to take into account the spectral properties of the underlying gain transition, its position and linewidth, as well as incorporating an arbitrary pump profile. We will combine two theoretical approaches to characterize the lasing properties of PM lasers: for two-dimensional systems, the generalized Lorenz-Mie theory will obtain the resonant modes of the coupled molecules in an active medium described by SALT. Not only is then the theoretical description more complete, the use of an active medium provides additional parameters to control, engineer and harness the lasing properties of PM lasers for ultra-low threshold and directional single-mode emission.