English
Related papers

Related papers: Effects due to generation of negative frequencies …

200 papers

The wave nature of light is revealed by diffraction from physical structures. We report a time-domain version of the classic Young's double-slit experiment: a beam of light twice gated in time produces an interference in the frequency…

We develop a theoretical framework for time-modulated acoustic metasurfaces comprising a line array of modulated cavities, and show that bound acoustic surface waves can undergo temporal diffraction from bound states localised at an…

Applied Physics · Physics 2025-12-22 E. Paul , G. J. Chaplain , J. Li , T. A. Starkey , S. A. R. Horsley

A technique for timescale analysis of spectral lags performed directly in the time domain is developed. Simulation studies are made to compare the time domain technique with the Fourier frequency analysis for spectral time lags. The time…

Astrophysics · Physics 2014-10-13 T. P. Li , J. L. Qu , H. Feng , L. M. Song , G. Q. Ding , L. Chen

We report a THz reflectarray metasurface which uses graphene as active element to achieve beam steering, shaping and broadband phase modulation. This is based on the creation of a voltage controlled reconfigurable phase hologram, which can…

Rapid modulation of the electromagnetic response in both time and space creates temporal boundaries in the medium and leads to time-reflection and time-refraction of light and to the eventual formation of the photonic time crystal within…

Optics · Physics 2024-10-01 Evgenii E. Narimanov

We solve the wave equation with periodically time-modulated material parameters in a one-dimensional high-contrast resonator structure in the subwavelength regime exactly, for which we compute the subwavelength quasifrequencies numerically…

Analysis of PDEs · Mathematics 2024-01-04 Habib Ammari , Jinghao Cao , Erik Orvehed Hiltunen , Liora Rueff

Adoption of terahertz technologies is hindered by the lack of cost-effective THz sources. Here we demonstrate a fundamentally new way to generate and control THz radiation, via spatio-temporal emissivity modulation. By patterning the…

This paper presents an analytical framework for the analysis of time-varying metal-based metamaterials. Concretely, we particularize the study to time-modulated metal-air interfaces embedded between two different semi-infinite media that…

Energy conversion in a physical system requires time-translation invariance breaking according to Noether's theorem. Closely associated with this symmetry-conservation relation, the frequencies of electromagnetic waves are found to be…

We report on broadband-to-narrowband elastic wave filtering resulting from time-periodic modulation of the stiffness of a one-dimensional elastic waveguide. Time modulation produces flat dispersion bands at frequencies that are multiple…

Applied Physics · Physics 2019-04-03 Giuseppe Trainiti , Yiwei Xia , Jacopo Marconi , Alper Erturk , Massimo Ruzzene

Materials with unusual optical properties are central to advanced control of light. Yet, in nature, such materials may be exceedingly rare and often difficult to obtain. To overcome this limitation, here we introduce the concept of temporal…

Optics · Physics 2026-05-19 Grigorii Ptitcyn , Diego M. Solís , M. S. Mirmoosa , Nader Engheta

Controlling waves in complex media has become a major topic of interest, notably through the concepts of time reversal and wavefront shaping. Recently, it was shown that spatial light modulators can counter-intuitively focus waves both in…

Classical Physics · Physics 2016-09-28 Philipp del Hougne , Fabrice Lemoult , Mathias Fink , Geoffroy Lerosey

When an excited electromagnetically open optical waveguide goes through a temporal transition of its material properties, it radiates to the ambient surroundings. In this letter, we explore this radiation and reveal, using asymptotic…

Optics · Physics 2024-09-19 Amir Shlivinski , Yakir Hadad

By exploiting singular spatial modulations of the graphene conductivity, we design a broadband, tunable THz absorber whose efficiency approaches the theoretical upper bound for a wide absorption band with a fractional bandwidth of 185\%.…

Mesoscale and Nanoscale Physics · Physics 2018-10-25 Emanuele Galiffi , John Pendry , Paloma Arroyo Huidobro

Electromagnetic temporal boundaries, emerging when the constitutive parameters of a medium undergo abrupt temporal variations, have garnered significant interest for their role in facilitating unconventional wave phenomena and enabling…

In order to confine waves beyond the diffraction limit, advances in fabrication techniques have enabled subwavelength structuring of matter, achieving near-field control of light and other types of waves. The price is often expensive…

Applied Physics · Physics 2020-09-23 Emanuele Galiffi , Yao-Ting Wang , Zhen Lim , J. B. Pendry , Andrea Alù , Paloma A. Huidobro

This paper presents a new method for generating low-frequency electromagnetic waves for navigation and communication in challenging environments, such as underwater and underground. The main idea is to store magnetic energy in two different…

Applied Physics · Physics 2020-05-21 Ali Hosseini-Fahraji , Majid Manteghi , Khai d. t. Ngo

We have fabricated a centimeter-size single-layer graphene device, with a gate electrode, which can modulate the transmission of terahertz and infrared waves. Using time-domain terahertz spectroscopy and Fourier-transform infrared…

An auditory neuron can preserve the temporal fine structure of a low-frequency tone by phase-locking its response to the stimulus. Apart from sound localization, however, little is known about the role of this temporal information for…

Neurons and Cognition · Quantitative Biology 2012-09-21 Tobias Reichenbach , A. J. Hudspeth

A subject's heart beat can be nearly invisible in a spectrum, when that spectrum is generated using conventional methods of Fourier analysis. The phenomenon has been observed in records of both electrocardiography type and…

General Physics · Physics 2010-11-09 Randall Peters , Erskine James , Michael Russell