Transmission enhancement in loss-gain multilayers by resonant suppression of reflection

Using the transfer-matrix approach and solving time-domain differential equations, we analyze the loss compensation mechanism in multilayer systems composed of an absorbing transparent conductive oxide and dielectric doped with an active material. We reveal also another regime with the possibility of enhanced transmission with suppressed reflection originating from the resonant properties of the multilayers. For obliquely incident and evanescent waves, such enhanced transmission under suppressed reflection turns into the reflectionless regime, which is similar to that observed in the PT-symmetric structures, but does not require PT symmetry. We infer that the reflectionless transmission is due to the full loss compensation at the resonant wavelengths of the multilayers.Comment: 12 pages, 10 figure

A New Approach of the Metatheory of Correct Programming. Rationale

This is first of a series of four papers, which are forming a foundation of a mathematical theory and metamathematics of correct computer programming. This papers contains the rationale of the choosing concepts in following three papers

Local field effect as a function of pulse duration

In this note we give semiclassical consideration of the role of pulse duration in observation of local field effects in the regime of optical switching. We show that the main parameter governing local field influence is the ratio of peak Rabi frequency corresponding to medium inversion and Lorentz frequency of the medium. To obtain significant local field effect, this parameter should be near unity that is valid only for long enough pulses. We also discuss the role of relaxation and pulse shape in this processes.Comment: 4 pages, 3 figure

Inverse problem in transformation optics

The straightforward method of transformation optics implies that one starts from the coordinate transformation, determines the Jacobian matrix, the fields and material parameters of the cloak. However, the coordinate transformation appears as an optional function: it is not necessary to know it. We offer the solution of some sort of the inverse problem: starting from the fields in the invisibility cloak we directly derive the permittivity and permeability tensors of the cloaking shell. The approach can be useful for finding material parameters for the specified electromagnetic fields in the cloaking shell without knowing coordinate transformation.Comment: 7 pages, 4 figures, J. Opt, vol. 13, 201

Pseudocanalization regime for magnetic dark-field hyperlens

Hyperbolic metamaterials (HMMs) are the cornerstone of the hyperlens, which brings the superresolution effect from the near-field to the far-field zone. For effective application of the hyperlens it should operate in so-called canalization regime, when the phase advancement of the propagating fields is maximally supressed, and thus field broadening is minimized. For conventional hyperlenses it is relatively straightforward to achieve canalization by tuning the anisotropic permittivity tensor. However, for a dark-field hyperlens designed to image weak scatterers by filtering out background radiation (dark-field regime) this approach is not viable, because design requirements for such filtering and elimination of phase advancement i.e. canalization, are mutually exclusive. Here we propose the use of magnetic ($\mu$-positive and negative) HMMs to achieve phase cancellation at the output equivalent to the performance of a HMM in the canalized regime. The proposed structure offers additional flexibility over simple HMMs in tuning light propagation. We show that in this ``pseudocanalizing'' configuration quality of an image is comparable to a conventional hyperlens, while the desired filtering of the incident illumination associated with the dark-field hyperlens is preserved