Silver film and distributed Bragg reflector microcavity: multilayered laser model threshold analysis

Abstract

The paper is devoted to the theoretical investigation of threshold conditions in layered microlaser structures combining a finite-thickness silver film and a dielectric distributed Bragg reflector (DBR). The research is motivated by the growing demand for compact and efficient coherent light sources that can be integrated into modern photonic and opto electronic systems. Microlasers based on hybrid metal–dielectric cavities attract considerable attention because they offer reduced size, low power consumption, and the potential for precise spectral control. At the same time, their operation is strongly affected by the reflectivity of cavity boundaries, the thickness of the active medium, and the presence of parasitic resonances. In this context, the present work focuses on analyzing how these structural factors determine the lasing threshold and spectral characteristics of operating modes. The study employs the Lasing Eigenvalue Problem ap proach, which enables a rigorous description of cavity modes at the emission threshold, and the Transfer Matrix Meth od, which is widely used for multilayer optical systems. The numerical results demonstrate that increasing the silver film thickness can noticeably reduce the lasing threshold, while adjustment of the active layer thickness provides efficient wavelength tuning in the visible and near-infrared ranges.