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A novel terahertz detector is here proposed, based on the use of planar arrays of graphene nanoribbons of different widths and lengths. Two distinct mechanisms are exploited to detect an external incident field: the excitation of interband transitions and of the surface plasmon polaritons resonances. The tuning of such mechanisms allows strengthening the signal, so providing an alternative solution to the problem of the low efficiency of the resonant graphene antennas. This paper proposes a possible design solution and analyzes and the feasibility of tuning the two mechanisms in the THz range.

We present a model of one-dimensional chain of two-level artificial atoms driven with DC field and quantum light simultaneously in a strong coupling regime. The interaction of atoms with light leads to electron-photon entanglement (dressing of the atoms with light). The driving via dc field leads to the Bloch oscillations (BO) in the chain of dressed atoms. We consider the mutual influence of dressing and BO and show that scenario of oscillations dramatically differs from predicted by the Jaynes-Cummings and Bloch-Zener models. We study the evolution of the population inversion, tunneling current, photon probability distribution, mean number of photons, and photon number variance, and show the influence of BO on the quantum-statistical characteristics of light. For example, the collapse-revivals picture and vacuum Rabi-oscillations are strongly modulated with Bloch frequency. As a result, quantum properties of light and degree of electron-photon entanglement become controllable via adiabatic dc field turning. On the other hand, the low-frequency tunneling current depends on the quantum light statistics (in particular, for coherent initial state it is modulated accordingly the collapse-revivals picture). The developed model is universal with respect to the physical origin of artificial atom and frequency range of atom-light interaction. The model is adapted to the 2D-heterostructures (THz frequencies), semiconductor quantum dots (optical range), and Josephson junctions (microwaves). The data for numerical simulations are taken from recently published experiments. The obtained results open a new way in quantum state engineering and nano-photonic spectroscopy.

We proposed the general concept of quantum antenna in the strong coupling regime. It is based on the theory of open quantum systems. The antenna emission to the space is considered as an interaction with the thermal photonic reservoir. For modeling of the antenna dynamics is formulated a master equation with the correspondent Lindblad super-operators as the radiation terms. It is shown that strong coupling dramatically changes the radiation pattern of antenna. The total power pattern splits to three partial components; each corresponds to the spectral line of Mollow triplet. We analyzed the dependence of splitting from the length of antenna, shift of the phase, and Rabi-frequency. The predicted effect opens a way for implementation of multi-beam electrically tunable antennas, potentially useful in different nano-devices.

We considered one-dimensional quantum chains of two-level Fermi particles coupled via the tunneling driven both by ac and dc fields in the regimes of strong and ultrastrong coupling. The frequency of ac field is matched with the frequency of the quantum transition. Based on the fundamental principles of electrodynamics and quantum theory, we developed a general model of quantum dynamics for such interactions. We showed that the joint action of ac and dc fields leads to the strong mutual influence of Rabi- and Bloch oscillations one to another. We focused on the regime of ultrastrong coupling, for which Bloch- and Rabi-frequencies are a significant values of the frequency of interband transition. The Hamiltonian was solved numerically with account of anti-resonant terms. It manifests by the appearance of great number of narrow high-amplitude resonant lines in the spectra of tunneling current and dipole moment. We proposed the new concept of THz spectroscopy promising for different applications in future nanoelectronics and nano-photonics., 26 pages, 20 figures

In this paper, we recast the problem of interaction between a classical electromagnetic field and a pair of quantum dots coupled through dipoledipole interaction in terms of an equivalent circuit model. Then, we use the introduced circuit to investigate the electromagnetic scattering from a pair of interacting quantum dots. Equivalent circuits for complex systems of quantum dots greatly simplify the analysis and the design of light-matter interaction processes at the nanoscale.

This paper introduces the concept of equivalent electrical multiport for a quantum device made of a pair of two-level objects, coupled via entanglement. The coupled pair is described in terms of an equivalent 2×2 admittance matrix, derived from the theory of the generalized susceptibility. This result provides a valuable tool to analyze quantum circuits in the frame of the classical circuit theory. The study of the properties of the admittance matrix highlights the effect of a new coupling mechanism, due to entanglement, which adds to the classical electromagnetic coupling.

The solution of the Poisson equation is an essential stage in the calculation of quantum properties of materials as it appears both in the electrostatic Hartree term and in the Fock exchange operator. We discuss here an integral method for the calculation of Poisson potential and demonstrate its integration with a Density Functional Theory (DFT) code. We show some results on elongated carbon chains.

The concept of electromagnetic crosstalk in nano-circuits via quantum entanglement between the elements is considered. Manifestation of this effect in electromagnetic compatibility (EMC) and a solution for for its suppression are discussed.

Electromagnetic (EM) absorption properties of a novel nanocarbon material - onion-like carbon (OLC) produced by annealing of detonation nanodiamonds (ND) in vacuum - have been studied in low-frequency, microwave and THz frequency ranges. It was proved experimentally that OLC EM absorption capacity can be optimized by varying the nanocarbon cluster size and ND annealing temperature so that effective EM coatings can be produced. Both the experimental observations and theoretical simulations demonstrate that small additions of OLC particles to a polymer host can noticeably modify the composite response to EM radiation. Open problems for a correct theoretical modeling of the EM response of such a complex composite are also discussed.

We present the electromagnetic scattering theory for a finite-length nanowire with an embedded mesoscopic object. The theory is based on a synthesis of the integral equation technique of classical electrodynamics and the quantum transport formalism. We formulate Hall\'en-type integral equations, where the canonical integral operators from wire antenna theory are combined with special terms responsible for the mesoscopic structure. The theory is applied to calculate the polarizability of a finite-length single-walled carbon nanotube (CNT) with a short low-conductive section (LCS) in the microwave and subterahertz ranges. The LCS is modeled as a multichannel two-electrode mesoscopic system. The effective resistive sheet impedance boundary conditions for the scattered field are applied on the CNT surface. It is shown that the imaginary part of the polarizability spectrum has three peaks. Two of them are in the terahertz range, while the third is in the gigahertz range. The polarizability spectrum of the CNT with many LCSs has only one gigahertz peak, which shifts to low frequencies as the number of LCSs increases. The physical nature of these peaks is explained, and potential applications of nanoantennas are proposed.