Energy Accumulation in a Functionally Graded Spatial-Temporal Checkerboard

Lurie, Konstantin A.; Onofrei, Daniel; Sanguinet, William; Weekes, Suzanne L.; Yakovlev, Vadim V.

doi:10.1109/lawp.2016.2647205

Cited by 11 publications

(5 citation statements)

References 7 publications

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“…Such fourdimensional compact apparatuses are endowed with unique properties not readily seen in conventional static metamaterials and metasurfaces. ST metasurfaces may take advantage of ST modulation capabilities, including nonreciprocal frequency generation [12], [16], [22], [23], parametric wave amplification [9], [24]- [26], asymmetric dispersion [27]- [29], and energy accumulation [30]. Frequency generation and nonreciprocity are of particular interest in ST-modulated (STM) slabs [16], [21], [22], [27], [29], [31]- [33], which are endowed by asymmetric periodic electromagnetic transitions in their dispersion diagram [13], [27], [28], [31], [34].…”

Section: Introductionmentioning

confidence: 99%

4D Wave Transformations Enabled by Space–Time Metasurfaces: Foundations and illustrative examples

Taravati

Eleftheriades

2023

IEEE Antennas Propag. Mag.

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Static metasurfaces have shown to be prominent compact structures for reciprocal and frequency-invariant transformation of electromagnetic waves in space. However, incorporating temporal variation to static metasurfaces enables dynamic apparatuses which are capable of four-dimensional tailoring of both the spatial and temporal characteristics of electromagnetic waves, leading to functionalities that are far beyond the capabilities of conventional static metasurfaces. This includes nonreciprocal full-duplex wave transmission, pure frequency conversion, parametric wave amplification, space-time (ST) decomposition, and space-time wave diffraction. This paper overviews our recent progress on analysis and functionalities of ST metasurfaces and slabs to break reciprocity. We study different operation regimes of ST metasurfaces such as scattering and diffraction at ST interfaces, ST sinusoidally-varying surfaces and slabs, as well as transmissive and reflective ST metasurfaces.

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Section: Introductionmentioning

confidence: 99%

4D Wave Transformations Enabled by Space–Time Metasurfaces: Foundations and illustrative examples

Taravati

Eleftheriades

2023

IEEE Antennas Propag. Mag.

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“…It eliminates issues of conventional nonreciprocity techniques, such as bulkiness, heaviness and incompatibility with integrated circuit technology associated with magnetbased nonreciprocity, power restrictions of nonlinear-based nonreciprocity, and frequency limitations and low power handling of transistor-based nonreciprocity. It provides asymmetric interband photonic transitions [7]- [14], subluminal and superluminal phase velocities, and asymmetric dispersion diagrams [4], [11], [13], [14], and holds potential for energy accumulation [15]. Various enhanced-efficiency magnet-free microwave and optical components have been recently realized by taking advantage of the unique properties of ST modulation, including isolators [9], [11], [16]- [19], circulators [20]- [23], Manuscript pure frequency mixer [24] metasurfaces [25]- [28], one-way beam splitters [12], [14], nonreciprocal antennas [29]- [31], and advanced wave engineering [32].…”

Section: Introductionmentioning

confidence: 99%

Space-Time Modulation: Principles and Applications

2020

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The ever-increasing demand for high data rate wireless systems has led to a crowded electromagnetic spectrum. This demand has successively spurred the development of versatile microwave and millimeter-wave integrated components possessing high selectivity, multi-functionalities and enhanced efficiency. These components require a class of nonreciprocal structures endowed with extra functionalities, e.g., frequency generation, wave amplification and full-duplex communication. Space-time (ST) modulation has been shown to be a perfect candidate for high data transmission given its extraordinary capability for electromagnetic wave engineering. Spacetime-modulated (STM) media are dynamic and directional electromagnetic structures whose constitutive parameters vary in both space and time. Recently, STM media have received substantial attention in the scientific and engineering communities. The unique and exotic properties of STM media have led to the development of original physics concepts, and novel devices in acoustics, microwave, terahertz and optic areas. STM media were initially studied in the context of traveling wave parametric amplifiers in the 50s and 60s [1]- [6]. In that era, magnet-based nonreciprocity was the dominant approach to the realization of isolators, circulators and other nonreciprocal systems. However, magnet-based nonreciprocity is plagued with bulkiness, nonintegrability, heaviness and incompatibility with high frequency techniques.Recently, ST modulation has experienced a surge in scientific attention thanks to its extraordinary and unique nonreciprocity. It eliminates issues of conventional nonreciprocity techniques, such as bulkiness, heaviness and incompatibility with integrated circuit technology associated with magnetbased nonreciprocity, power restrictions of nonlinear-based nonreciprocity, and frequency limitations and low power handling of transistor-based nonreciprocity. It provides asymmetric interband photonic transitions [7]-[14], subluminal and superluminal phase velocities, and asymmetric dispersion diagrams [4], [11], [13], [14], and holds potential for energy accumulation [15]. Various enhanced-efficiency magnet-free microwave and optical components have been recently realized by taking advantage of the unique properties of ST modulation, including isolators [9], [11], [16]-[19], circulators [20]-[23],

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“…Specifically, it has been used in [8] to achieve a better impedance matching between TL and reactive loads for short-time pulses, by [27] for the purpose of anti-reflection coating, and by [11] to improve the reflection bandwidth of a Dallenbach screen. Furthermore, the problem of reflection and transmission, as well as energy balance, in the presence of abrupt and gradual temporal variation of the guiding medium were explored in [30][31][32][33][34][35][36][37][38][39]. Scattering and radiation by time-modulated small obstacles that can be described using the dipole approximation have been explored in [40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Absorption and scattering by a temporally switched lossy layer: Going beyond the Rozanov bound

Firestein¹,

Shlivinski²,

Hadad³

2021

Preprint

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In this paper we study the electromagnetic scattering, absorption, and bounds for short time modulated pulses that impinge on a time-varying lossy layer that is sandwiched between vacuum and a perfect electric conductor. The electric characteristics of the layer, namely, the conductivity, permittivity, and permeability are assumed to change abruptly in time. The analysis is carried out using the equivalent transmission line (TL) model of the actual electromagnetic system. Thus, it naturally take into account the effect of polarization (TE and TM) as well as the effect of the angle of incidence, by simply introducing the proper TL characteristics. After formulating the onedimensional TL problem in the complex temporal frequency variable s, we apply the inverse Laplace transform to find the signals in time. Specifically, we show that the spectral Green's function in the s plane possesses no branch point singularities but exhibits only simple pole singularities, and thus we use this fact to substantially accelerate the calculation of the inverse Laplace transform.As an important application we demonstrate numerically that a time-varying absorbing layer that undergoes temporal switching of its conductance only can absorb the power of a modulated, ultrawideband, as well as a quasi-monochromatic, pulsed wave beyond what is dictated by the Rozanov bound when integrating over the whole frequency spectrum.

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Energy Accumulation in a Functionally Graded Spatial-Temporal Checkerboard

Cited by 11 publications

References 7 publications

4D Wave Transformations Enabled by Space–Time Metasurfaces: Foundations and illustrative examples

4D Wave Transformations Enabled by Space–Time Metasurfaces: Foundations and illustrative examples

Space-Time Modulation: Principles and Applications

Absorption and scattering by a temporally switched lossy layer: Going beyond the Rozanov bound

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