Time domain radiation and absorption by subwavelength sources

TL;DR

This paper investigates the unique energy flux characteristics of electromagnetic and acoustic subwavelength sources in the time domain, revealing a trade-off between emission and absorption that impacts wave radiation and focusing techniques.

Contribution

It uncovers fundamental features of wave radiation from subwavelength sources and discusses implications for subwavelength focusing using time reversal with active sources.

Findings

Time-domain energy flux shows a trade-off between emission and absorption.

Behavior is universal across classical wave types.

Implications for subwavelength focusing techniques.

Abstract

Radiation by elementary sources is a basic problem in wave physics. We show that the time-domain energy flux radiated from electromagnetic and acoustic subwalength sources exhibits remarkable features. In particular, a subtle trade-off between source emission and absorption underlies the mechanism of radiation. This behavior should be observed for any kind of classical waves, thus having broad potential implications. We discuss the implication for subwavelength focusing by time reversal with active sources.