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Related papers: Three-Dimensional Cloaking Device Operates at Tera…

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Terahertz time-domain spectroscopy (THz-TDS) employs sub-picosecond pulses to probe dielectric properties of materials giving as a result a 3-dimensional hyperspectral data cube. The spatial resolution of THz images is primarily limited by…

Terahertz (THz) channel propagation characteristics are vital for the design, evaluation, and optimization for THz communication systems. Moreover, reflection plays a significant role in channel propagation. In this letter, the reflection…

Signal Processing · Electrical Eng. & Systems 2022-07-12 Zhaowei Chang , Jianhua Zhang , Pan Tang , Lei Tian , Li Yu , Guangyi Liu , Liang Xia

A parallel dispersive finite-difference time-domain (FDTD) method for the modeling of three-dimensional (3-D) electromagnetic cloaking structures is presented in this paper. The permittivity and permeability of the cloak are mapped to the…

Computational Physics · Physics 2015-05-13 Yan Zhao , Yang Hao

Invisibility or unhearability cloaks have been made possible by using metamaterials making light or sound flow around obstacle without the trace of reflections or shadows. Metamaterials are known for being flexible building units that can…

Terahertz (THz) near-field imaging is a flourishing discipline [1], with applications from fundamental studies of beam propagation [2,3] to the characterisation of metameterials [4,5] and waveguides [6,7]. Beating the diffraction limit…

Manipulating broadband fields in scattering media is a modern challenge across photonics and other wave domains. Recent studies have shown that complex propagation in scattering media can be harnessed to manipulate broadband light wave…

THz time domain spectroscopy is a powerful technique enabling the investigation of different materials in the far-infrared frequency range. Even if nowadays this technique is well established, its application to very thin films remains…

Instrumentation and Detectors · Physics 2024-06-07 A. Taschin , P. Bartolini , J. Tasseva , R. Torre

We study the approximate cloaking via transformation optics for electromagnetic waves in the time harmonic regime in which the cloaking device {\it only} consists of a layer constructed by the mapping technique. Due to the fact that…

Analysis of PDEs · Mathematics 2018-11-02 Hoai-Minh Nguyen , Loc Tran

Traditional imaging systems, such as the eye or cameras, image scenes that lie in the direct line-of-sight (LoS). Most objects are opaque in the optical and infrared regimes and can limit dramatically the field of view (FoV). Current…

Optics · Physics 2022-05-11 Yiran Cui , Georgios C. Trichopoulos

We consider how transformation optics and invisibility cloaking can be used to construct models in subsets $\mathbb{R}^3$ with a varying metric, where the time-harmonic waves for a given angular wavenumber $k$, are equivalent to the waves…

Analysis of PDEs · Mathematics 2021-03-26 Tracey Balehowsky , Matti Lassas , Pekka Pankka , Ville Sirviö

The electromagnetic characteristics of plane-transformed invisibility cloaks are quantitatively studied in this paper. We take elliptical cylindrical cloak as the example, and use an elliptical cylindrical wave expansion method to obtain…

Optics · Physics 2015-05-13 Yu Luo , Jingjing Zhang , Hongsheng Chen , Lixin Ran , Bae-Ian Wu , Jin Au Kong

Invisibility cloaking in acoustic scattering via the approach of transformation optics is considered. The near-cloaks of both passive medium and active/radiating object are investigated. From a practical viewpoint, we are especially…

Analysis of PDEs · Mathematics 2012-11-12 Hongyu Liu

Near-field scanning optical microscopy is a powerful technique for imaging below the diffraction limit, which has been extensively used in bio-medical imaging and nanophotonics. However, when the electromagnetic fields under measurement are…

Using a sum rule, we derive new bounds on Herglotz functions that generalize those given in (Gustafson and Sj\"oberg 2010) and (Bernland, Luger and Gustafson 2011). These bounds apply to a wide class of linear passive systems such as…

Mathematical Physics · Physics 2017-08-02 Maxence Cassier , Graeme W. Milton

Based on the transformation optics, a novel transmission-line (TL) approach to realize invisibility cloaking using planar anisotropic metamaterials (MTMs) is proposed. The two-dimensional cylindrical cloaks are modeled based on…

Classical Physics · Physics 2015-05-14 Xiao Liu , Chao Li , Kan Yao , Xiankun Meng , Fang Li

Invisibility cloaks for flexural waves have been mostly examined in the continuous-wave regime, while invisibility is likely to deteriorate for short pulses. Here, we propose the practical realization of a unidirectional invisibility cloak…

Classical Physics · Physics 2023-08-02 Kun Tang , Eitam Luz , David Amram , Luna Kadysz , Sebastien Guenneau , Patrick Sebbah

In this study, the design of a directional cloaking based on the Luneburg lens system is proposed and its operating principle is experimentally verified. The cloaking concept is analytically investigated via geometrical optics and…

Applied Physics · Physics 2019-04-30 Ceren Babayigit , Aydin Sinan Evren , Emre Bor , Hamza Kurt , Mirbek Turduev

Terahertz microscopy has attracted attention owing to distinctive characteristics of the THz frequency region, particularly non-ionizing photon energy, spectral fingerprint, and transparency to most nonpolar materials. Nevertheless, the…

There is currently a great deal of interest in the invisibility cloaks recently proposed by Pendry et al. that are based in the transformation approach. They obtained their results using first order transformations. In recent papers Hendi…

Optics · Physics 2009-11-13 Ricardo Weder

Terahertz coloured digital holography ranging from 1.39 THz up to 4.25 THz is demonstrated. It is shown that it can be applied for the investigation of low-absorbing objects, and it is illustrated via inspection of stacked graphene layers…