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We measured a change in the current transport of an antenna-coupled, multi-gate, GaAs/AlGaAs field-effect transistor when terahertz electromagnetic waves irradiated the transistor and attribute the change to bolometric heating of the…

Mesoscale and Nanoscale Physics · Physics 2016-05-11 Gregory C. Dyer , Gregory R. Aizin , Sascha Preu , N. Q. Vinh , S. James Allen , John L. Reno , Eric A. Shaner

Urbach tails in semiconductors are often associated to effects of compositional disorder. The Urbach tail observed in InGaN alloy quantum wells of solar cells and LEDs by biased photocurrent spectroscopy is shown to be characteristic of the…

We demonstrated an ultra-broadband, polarization-insensitive and wide-angle metamaterial absorber for terahertz (THz) frequencies using arrays of truncated pyramid unit structure made of metal-dielectric multilayer composite. In our design…

Optics · Physics 2014-06-02 Jianfei Zhu , Zhaofeng Ma , Wujiong Sun , Fei Ding , Qiong He , Lei Zhou , Yungui Ma

We study the emission spectrum and absorption spectrum of a quantum emitter when it is driven by various pulse sequences. We consider the Uhrig sequence of $\pi_x$ pulses, the periodic sequence of $\pi_x\pi_y$ pulses and the periodic…

Quantum Physics · Physics 2018-04-25 Herbert F Fotso

A statistical analysis of the space-time distribution of absorption-line systems (ALSs) observed in QSO spectra within the cosmological redshift interval $z$=0.0--3.7 is carried out on the base of our catalog of absorption systems…

Astrophysics · Physics 2008-11-26 A. I. Ryabinkov , A. D. Kaminker , D. A. Varshalovich

A short introduction of a relation between a Green's function and a quantum wave impedance function as well as its application to a determination of eigenenergies and eigenfunctions of a quatum-mechanical system is provided. Three different…

Quantum Physics · Physics 2020-10-13 O. I. Hryhorchak

In practice, the finite number of samples of the spherical radiation pattern or antenna gain are taken on the sphere for both the reconstruction of the antenna radiation pattern and the computation of mobile handset performance measures…

Signal Processing · Electrical Eng. & Systems 2018-12-03 Umair Ahmed , Zubair Khalid

The influence of the growth conditions as well as the device design on the device performance of (GaIn)As/Ga(AsSb)/(GaIn)As "W"-quantum well lasers is investigated. To this purpose, the epitaxy process is scaled to full two inch substrates…

Energy level structure and direct light absorption in a cylindrical quantum dot, having thin falciform cross section, are studied within the framework of the adiabatic approximation. An analytical expression for the energy spectrum of the…

Mesoscale and Nanoscale Physics · Physics 2015-05-08 Karen G. Dvoyan , David B. Hayrapetyan , Eduard M. Kazaryan , Ani A. Tshantshapanyan

In this paper, we consider the Schwarzschild-Tangherlini black hole to investigate the process of scalar wave scattering by the black hole in a spacetime of (d + 1) dimensions and also with the generalized uncertainty principle (GUP). In…

General Relativity and Quantum Cosmology · Physics 2024-07-11 M. A. Anacleto , J. A. V. Campos , F. A. Brito , E. Maciel , E. Passos

In this work, we numerically investigate the scattering and absorption cross section of the massless scalar field from some well-known regular black holes by using the partial wave approach. Our computational results indicate that the…

General Relativity and Quantum Cosmology · Physics 2022-12-07 Mao-Yuan Wan , Chen Wu

Terahertz photoconductivity of $100~\mu$m and $20~\mu$m Hall bars fabricated from narrow AlAs quantum wells (QWs) of different widths is investigated in this paper. The photoresponse is dominated by collective magnetoplasmon excitations…

The design of a self-complementary metallic checkerboard pattern achieves broadband, dispersion-less, and maximized absorption, concentrating in the deep subwavelength resistive connections between squares, without any theoretical…

We have studied a series of InAs/GaSb coupled quantum wells using magneto-infrared spectroscopy for high magnetic fields up to 33T within temperatures ranging from 4K to 45K in both Faraday and tilted field geometries. This type of coupled…

Strongly Correlated Electrons · Physics 2015-05-18 L. -C. Tung , P. A. Folkes , G. Gumbs , W. Xu , Y. J. Wang

The photoabsorption spectra of calcium-doped argon clusters CaAr_n are investigated at thermal equilibrium using a variety of theoretical and numerical tools. The influence of temperature on the absorption spectra is estimated using the…

Chemical Physics · Physics 2009-11-07 F. Calvo , F. Spiegelman , M. C. Heitz

The absorption rate of low-energy, or soft, electromagnetic radiation by spherically symmetric black holes in arbitrary dimensions is shown to be fixed by conservation of energy and large gauge transformations. We interpret this result as…

High Energy Physics - Theory · Physics 2017-04-26 Steven G. Avery , Burkhard U. W. Schwab

In terms of the complex angular momentum method, we compute the absorption cross section by analyzing a massless test scalar field around conformally related black holes. At first, we investigate circular null geodesics and thereby prove a…

General Relativity and Quantum Cosmology · Physics 2022-02-22 Yang Li , Yan-Gang Miao

Metasurface based super absorbers exhibit near unity absorbance. While the absorption peak can be tuned by the geometry/size of the sub-wavelength resonator, broadband absorption can be obtained by placing multiple resonators of various…

Materials Science · Physics 2019-04-03 Arvind Nagarajan , Kumar Vivek , Manav Shah , Venu Gopal Achanta , Giampiero Gerini

This paper develops a unified framework to maximize the network sum-rate in a multi-user, multi-BS downlink terahertz (THz) network by optimizing user associations, number and bandwidth of sub-bands in a THz transmission window (TW),…

Information Theory · Computer Science 2024-08-08 Mohammad Amin Saeidi , Hina Tabassum , Mehrazin Alizadeh

In the aim to find the simplest and most efficient shape of a noise absorbing wall to dissipate the acoustical energy of a sound wave, we consider a frequency model described by the Helmholtz equation with a damping on the boundary. The…

Analysis of PDEs · Mathematics 2020-07-23 Frédéric Magoulès , Thi Phuong Kieu Nguyen , Pascal Omnes , Anna Rozanova-Pierrat