Oksana V. Shramkova

Scattering properties of PT- symmetric layered periodic structures

The optical properties of PT-symmetric periodic stack of the layers with balanced loss and gain are examined. We demonstrate that tunnelling phenomenon in periodic structures is connected with excitation of surface waves at the boundaries separating gain and loss regions within each unit cell and tunnelling conditions for periodic stack can be reduced to the conditions for one period. Alternatively, it is shown that coherent perfect absorber laser states are mediated by excitation of surface modes localised at all internal boundaries of the structure. The effects of the structure parameters and angle and direction of incidence on the resonant phenomena and spontaneous symmetry breaking transition are determined. It is shown that structure periodicity significantly increases the number of resonant phenomena, especially in stacks with high real and imaginary parts of dielectric permittivity of the layers. Gaussian beam dynamics in this type of structure is examined. The beam splitting in PT-symmetric periodic structure is observed.

Resonant Combinatorial Frequency Generation Induced by a PT -Symmetric Periodic Layered Stack

The nonlinear interaction of waves in PT-symmetric periodic stacks with an embedded nonlinear anisotropic dielectric layer illuminated by plane waves of two tones is examined. The three-wave interaction technique is applied to study the nonlinear processes. It is shown that the intensity of the three-wave mixing process can be significantly enhanced in resonant cavities based on PT-symmetric periodic structures, especially as the pumping wave frequency is near the coherent perfect absorber-lasing resonances. The main mechanisms and properties of the combinatorial frequency generation and emission from the stacks are illustrated by the simulation results and the effect of the layer arrangement in PT-symmetric walls of resonator on the stack nonlinear response is discussed. The enhanced efficiency of the frequency conversion at Wolf-Bragg resonances is demonstrated. It has been shown that Wolf-Bragg resonances of very high orders may lead to the global maxima and nulls of the scattered field. The analysis of the effect of losses in nonlinear dielectric layer on the combinatorial frequency generation efficiency has shown that the rate of losses may amplify the intensity of the frequency mixing process.

Nonreciprocal scattering by PT-symmetric stack of the layers

The nonreciprocal wave propagation in PT-symmetric periodic stack of binary dielectric layers characterised by balances loss and gain is analysed. The main mechanisms and resonant properties of the scattered plane waves are illustrated by the simulation results, and the effects of the periodicity and individual layer parameters on the stack nonreciprocal response are discussed. Gaussian beam dynamics in this type of structure is examined. The beam splitting in PT-symmetric periodic structure is observed. It is demonstrated that for slant beam incidence the break of the symmetry of field distribution takes place.

Corrections to “Resonant Combinatorial Frequency Generation Induced by a PT-Symmetric Periodic Layered Stack” [Sep/Oct 16 DOI: 10.1109/JSTQE.2015.2505139]

In the above paper [1], there is an error on page 1, left column, second line of the first paragraph of the footnote. The statement “This work was supported in part by the European Union Seventh Framework Program (FP7-REGPOT-2012-2013-1) under Grant agreement 316165.” should instead be corrected to “This work was supported in part by the European Union Seventh Framework Program (FP7-REGPOT-2012-2013-1) under Grant agreement 316165, the Ministry of Education and Science of the Russian Federation in the framework of the Increase Competitiveness Program of NUST “MISiS” (No. K2-2015-007).”

Resonant combinatorial frequency generation in non-Hermitian hyperbolic metamaterials

The properties of the combinatorial frequency generation by the periodic semiconductor-dielectric multilayers with hyperbolic dispersion are explored. The nonlinear wave scattering process has been modelled in a self-consistent problem formulation, taking into account the nonlinear dynamics of carriers in semiconductor material. We show that incorporating gain within the multilayer system not only renders the compensation of the semiconductor loss but also significantly enhances the nonlinear interactions in the semiconductor stacks with resistive nature of nonlinearity.