Hawking- type radiation in transluminal gratings

Article Nanoscience & Nanotechnology

Replicating physical motion with Minkowskian isorefractive spacetime crystals

Filipa R. Prudencio et al.

Summary: In this study, it is demonstrated that isorefractive spacetime crystals with a travelling-wave modulation can rigorously mimic the response of moving material systems. Unlike generic spacetime crystals, which exhibit bi-anisotropic coupling in the co-moving frame, isorefractive crystals show an observer-independent response, resulting in isotropic constitutive relations without any bianisotropy. The researchers show how this property can be utilized in calculating the band diagrams of isorefractive spacetime crystals in the laboratory frame and studying synthetic Fresnel drag. Additionally, the impact of considering either a Galilean or a Lorentz transformation in the homogenization of spacetime crystals is discussed, revealing that the effective response is independent of the transformation considered.

NANOPHOTONICS (2023)

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Article Multidisciplinary Sciences

Quantum electrodynamics of time-varying gratings

Simon A. R. Horsley et al.

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (2023)

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Review Optics

Photonics of time-varying media

Emanuele Galiffi et al.

Summary: This review comprehensively discusses the recent progress of time modulation in photonic metamaterials, including temporal switching, photonic time-crystals, and spatiotemporal modulation. It also reviews and provides perspectives on the applications of time modulation in nonreciprocity, synthetic motion, giant anisotropy, etc.

ADVANCED PHOTONICS (2022)

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Article Physics, Multidisciplinary

Cerenkov radiation in vacuum from a superluminal grating

Daigo Oue et al.

Summary: This paper theoretically predicts the generation of Cerenkov radiation (CR) in vacuum through spatiotemporally modulated boundary. By quantitatively evaluating the scattered fields, it is found that all fields are evanescent when the modulation speed is slower than light, while some become propagating when the modulation is faster than light.

PHYSICAL REVIEW RESEARCH (2022)

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Article Optics

Gain mechanism in time-dependent media

J. B. Pendry et al.

Summary: Traditionally, time-dependent systems add energy to electromagnetic waves by parametric amplification. However, this study introduces a new mechanism of energy addition through compression of lines of force.

OPTICA (2021)

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Article Physics, Applied

Homogenization Theory of Space-Time Metamaterials

P. A. Huidobro et al.

Summary: The paper introduces a general framework for the homogenization theory of space-time metamaterials, deriving analytical formulas for effective material parameters in the low-frequency limit for traveling-wave modulations. It shows how synthetic motion can lead to giant bianisotropy and how modulation speed and phase can tune the nonreciprocal response. The theory is applied to derive exact formulas for the Fresnel drag in electromagnetic media with traveling-wave modulations, providing insight into differences and similarities between synthetic motion and moving matter.

PHYSICAL REVIEW APPLIED (2021)

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Article Multidisciplinary Sciences