Spatial Coherence of Thermal Emission Associated with Coherent Perfect Absorption

Coherent perfect absorption (CPA) is an interference process in which the combination of input signals leads to complete absorption. Mathematically, it is derived from the scattering matrix S. CPA, when based on multiple input signals, allows light-light interactions in linear systems, with natural applications in interferometry, sensing, and optical data processing. Our theoretical analysis reveals new features of CPA: orthogonal channels between thermal noise and transmission signals, which allow heat exchange within confined thermal networks [1]. These findings provide insight into the physics of CPA and its potential uses in heat management, nanophotonic thermal engines, and CPA technologies.