Purcell Enhancement Near Arbitrary Anisotropic Multilayers: From Plasmonic Layers to Twisted Hyperbolic Stacks (MATLAB files)

This repository contains MATLAB code for calculating the emission properties of a dipole above a planar multilayer structures containing arbitrarily anisotropic materials. The implementation uses the Passler–Paarmann transfer-matrix formalism (Passler, Nikolai Christian, et al. Physical Review B (2023) and associated code at the following zenodo link) to evaluate polarization-resolved Fresnel reflection coefficients as functions of wavelength, azimuthal angle, and normalized in-plane wavevector. An adaptive wavevector-grid refinement procedure is used to resolve sharp polaritonic resonances and to guide the numerical evaluation of the associated Sommerfeld integrals. The code calculates orientation-dependent Purcell factors, radiative and nonradiative decay rates, normalized emitter lifetimes, upper-half-space radiation patterns, and emission from arbitrarily oriented in-plane dipoles. The included example considers a dipole above a semi-infinite substrate of the biaxial crystal MoOCl₂. Additional sections provide diagnostics of the refined wavevector grid and Sommerfeld integrands, convergence tests for the numerical integration, and a comparison with finite-difference time-domain simulations.This software is associated with the manuscript "Purcell Enhancement Near Arbitrary Anisotropic Multilayers: From Plasmonic Layers to Twisted Hyperbolic Stacks" currently under revision at Optics Express. The complete bibliographic reference and article DOI will be added to this record upon publication.