Abstract
It is well known that the quasinormal modes (or resonant states) of photonic structures can be associated with the poles of the scattering matrix of the system in the complex-frequency plane. In this work, the inverse problem, i.e., the reconstruction of the scattering matrix from the knowledge of the quasinormal modes, is addressed. We develop a general and scalable quasinormal-mode expansion of the scattering matrix, requiring only the complex eigenfrequencies and the far-field properties of the eigenmodes. The theory is validated by applying it to illustrative nanophotonic systems with multiple overlapping electromagnetic modes. The examples demonstrate that our theory provides an accurate first-principle prediction of the scattering properties, without the need for postulating ad-hoc nonresonant channels.
Highlights
Scattering matrices have been playing a ubiquitous role in physics since the early history of quantum field theory [1]
It is well known that the quasinormal modes of photonic structures can be associated with the poles of the scattering matrix of the system in the complex-frequency plane
Nowadays, scattering-matrix techniques represent an irreplaceable tool for scientists working in nuclear physics [2], electronic transport [3], or classically chaotic systems [4], just to mention some of the several fields of application
Summary
Scattering matrices have been playing a ubiquitous role in physics since the early history of quantum field theory [1]. We establish such a connection and we present a general theory to expand the scattering matrix on the quasinormal modes of photonic systems, which can be directly scaled to any number of eigenmodes and incoming or outgoing channels. Modal methods offer a deeper physical insight into the properties of resonant systems, because they allow us to draw a connection between the origin of complicated spectral features and the characteristics of the underlying quasinormal modes For these reasons, they are suitable for describing, understanding, and optimizing complex photonic systems. III, we numerically validate the theory in the illustrative cases of photonic crystal slabs and multilayered metallic nanoparticles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
