# Floquet analysis of excitations in materials

## TL;DR

This paper reviews how Floquet theory helps understand and analyze excitations and phase changes in materials induced by external laser fields, emphasizing experimental signatures and recent realizations of Floquet phases in solids.

## Contribution

It provides a comprehensive overview of Floquet analysis in materials, highlighting recent experimental progress and the theoretical framework for understanding non-equilibrium electronic states.

## Key findings

- Floquet theory offers a new perspective on excitations in solids.
- Experimental signatures of Floquet phases have been observed in various materials.
- Floquet engineering enables control over material properties using external lasers.

## Abstract

Controlled excitation of materials can transiently induce changed or novel properties with many fundamental and technological implications. Especially, the concept of Floquet engineering, manipulation of the electronic structure via dressing with external lasers, has attracted some recent interest. Here we review the progress made in defining Floquet materials properties and give a special focus on their signatures in experimental observables as well as considering recent experiments realizing Floquet phases in solid state materials. We discuss how a wide range of experiments with non-equilibrium electronic structure can be viewed by employing Floquet theory as an analysis tool providing a different view of excitations in solids.