Time-periodic (Floquet) systems in classical wave physics and engineering: Opinion

TL;DR

This paper reviews the physics and engineering of classical wave systems with time-periodic modulations, highlighting their potential to break reciprocity and surpass theoretical limits, inspired by analogous quantum phenomena.

Contribution

It provides a comprehensive overview of Floquet systems in classical wave physics, emphasizing recent advances and future challenges in engineering applications.

Findings

Time-periodic modulations enable nonreciprocal wave propagation.

Floquet engineering can overcome fundamental performance bounds.

The field is rapidly evolving with promising practical applications.

Abstract

The study of classical waves in time-periodic systems is experiencing a resurgence of interest, motivated by their rich physics and the new engineering opportunities they enable, with several analogies to parallel efforts in other branches of physics, e.g., Floquet-engineered quantum materials and time crystals. Here, we first briefly review some of the most prominent features enabled by time-periodic modulations, and we then focus on two specific areas, namely, time-varying systems to break reciprocity and to overcome various theoretical limitations and performance bounds, discussing their current status, challenges, and opportunities.