Floquet–Mie Theory for Time‐Varying Dispersive Spheres. Issue 3 (29th December 2022)

• Record Type: Journal Article
• Authors: Ptitcyn, Grigorii; Lamprianidis, Aristeidis; Karamanos, Theodosios; Asadchy, Viktar; Alaee, Rasoul; Müller, Marvin; Albooyeh, Mohammad; Mirmoosa, Mohammad Sajjad; Fan, Shanhui; Tretyakov, Sergei; Rockstuhl, Carsten
• Is Part Of: Laser & photonics reviews. Volume 17:Issue 3(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-29
• Subjects: light–matter interactions -- Mie scattering -- time‐modulation -- time‐varying media; Lasers -- Periodicals; Photonics -- Periodicals; Lasers -- Périodiques; Photonique -- Périodiques; 621.36
• DOI: 10.1002/lpor.202100683
• Languages: English
• ISSNs: 1863-8880

Abstract

Abstract: Exploring the interaction of light with time‐varying media is an intellectual challenge that, in addition to fundamental aspects, provides a pathway to multiple promising applications. Time modulation constitutes here a fundamental handle to control light on entirely different grounds. That holds particularly for complex systems simultaneously structured in space and time. However, a realistic description of time‐varying materials requires considering their material dispersion. The combination thereof has barely been considered but is crucial since dispersion accompanies materials suitable for dynamic modulation. As a canonical scattering problem from which many general insights can be obtained, a self‐consistent analytical theory of light scattering by a sphere made from a time‐varying material exemplarily assumed to have a Lorentzian dispersion is developed and applied. The eigensolutions of Maxwell's equations in the bulk are discussed and a dedicated Mie theory is presented. The proposed theory is verified with full‐wave simulations. Peculiar effects are disclosed, such as energy transfer from the time‐modulation subsystem to the electromagnetic field, amplifying carefully structured incident fields. Since many phenomena can be studied on analytical grounds with the proposed formalism, it represents an indispensable tool that enables exploration of electromagnetic phenomena in time‐varying and spatially structured finite objects of other geometries. Abstract : This work proposes a route to unify frequency dispersion and time‐modulation, which currently are bottlenecks in time‐varying models. The insights of the work can be quickly applied to time‐varying transparent oxides and plasmas operating in the near‐zero‐epsilon regime, where dispersion is of utmost importance. Scattering on a time‐varying sphere represents an initial step toward dynamic artificial materials with frequency dispersion.