Energy Absorption Interferometry

TL;DR

Energy Absorption Interferometry (EAI) is a versatile technique for characterizing how complex systems absorb energy across different excitation types, with new methods for sampling, noise analysis, and mode reconstruction presented.

Contribution

This paper provides a comprehensive theoretical overview of EAI and introduces novel techniques for sampling, phase referencing, mode reconstruction, and noise analysis.

Findings

Analysis of noise propagation in EAI experiments

Development of a noise model for spectral and modal errors

Enhanced methods for mode reconstruction and phase referencing

Abstract

Energy Absorption Interferometry (EAI) is a technique for measuring the responsivities and complex-valued spatial polarimetric forms of the individual degrees of freedom through which a many-body system can absorb energy. It was originally formulated using the language of quantum correlation functions, making it applicable to different kinds of excitation (electromagnetic, elastic and acoustic fields). EAI has been applied in a variety of theoretical and experimental ways. It is particularly effective at characterising the multimode behaviour of ultra-low-noise far-infrared and optical devices, imaging arrays, and complete instruments, where it can be used to ensure that a system is maximally responsive to those partially coherent fields that carry signal whilst avoiding those that only carry noise. Despite its utility there is no comprehensive overview of electromagnetic EAI. In this paper we describe the theoretical foundations of the method, and present a range of new techniques in areas relating to sampling, phase referencing, mode reconstruction and noise. We present, for the first time, an analysis of how noise propagates through an experiment resulting in errors and artefacts on spectral and modal plots. A noise model is essential, because it determines the signal to noise ratio needed to ensure a given level of experimental fidelity.