Orthogonal thermal noise and transmission signals: A new coherent perfect absorption's feature

TL;DR

This paper reveals that coherent perfect absorption thermal noise signals are orthogonal to transmitted signals, enabling novel thermal noise management and offering new insights into CPA-based technologies.

Contribution

It uncovers the orthogonality property of CPA thermal noise signals and explores its implications for thermal noise management and optical network design.

Findings

CPA thermal noise signals are orthogonal to transmitted signals

Orthogonality enables physical separation of thermal noise and signals

Supports development of externally lossless optical networks

Abstract

Coherent perfect absorption (CPA) is an interference process associated with the zeros of the scattering matrix that enables light-with-light interactions in linear systems, of interest for optical computing, data processing and sensing. However, the noise properties of CPA remain relatively unexplored. Here, we demonstrate that CPA thermal noise signals exhibit a unique property: they are orthogonal to the signals transmitted through the network. In turn, such property enables a variety of thermal noise management effects, such as the physical separability of thermal noise and transmitted signals, and "externally lossless" networks that internally host radiative heat transfer processes. We believe that our results provide a new perspective on the many CPA technologies currently under development.