Pavel L. Mladyonov

Asymmetric propagation of electromagnetic waves through a planar chiral structure

We report the first experiential observation and theoretical analysis of the new phenomenon of planar chiral circular conversion dichroism, which in some aspects resembles the Faraday effect in magnetized media, but does not require the presence of a magnetic field for its observation. It results from the interaction of an electromagnetic wave with a planar chiral structure patterned on the sub-wavelength scale, and manifests itself in asymmetric transmission of circularly polarized waves in the opposite directions through the structure and elliptically polarized eigenstates. The new effect is radically different from conventional gyrotropy of three-dimensional chiral media.

Mirror that does not change the phase of reflected waves

We report that electromagnetic wave reflected from a flat metallic mirror superimposed with a planar wavy metallic structure with subwavelength features that resemble “fish scales” reflects like a conventional mirror without diffraction, but shows no phase change with respect to the incident wave. Such unusual behavior resembles a reflection from a hypothetical zero refractive index material, or “magnetic wall”. We also discovered that the structure acts as a local field concentrator and a resonant “amplifier” of losses in the underlying dielectric.

Electromagnetic Wave Diffraction By Planar Periodic Gratings of Wavy Metal Strips

Numerical solution of electromagnetic wave diffraction by a two-periodic grating of wavy metal strips placed on a dielectric substrate is obtained. The solution is verified for a particular case of straight strips by comparison with the rigorous solution. Analytical expressions for the reflection coefficients from wavy gratings in free space are obtained in the low frequency range. Frequency dependencies of the reflection coefficients are analyzed. Differences in reflection from classical one-periodic gratings of straight strips are discussed.

Nonlinear interaction of two trapped-mode resonances in a bilayer fish-scale metamaterial

We report on a bistable light transmission through a bilayer “fish-scale” (meander-line) metamaterial. It is demonstrated that an all-optical switching may be achieved that is nearly the frequency of the high-quality-factor Fano-shaped trapped-mode resonance excitation. The nonlinear interaction of two closely spaced trapped-mode resonances in the bilayer structure composed with a Kerr-type nonlinear dielectric slab is analyzed in both frequency and time domains. It is demonstrated that these two resonances react differently on the applied intense light, which leads to destination of a multistable transmission.

Optical magnetic mirror

We report demonstration of an optical magnetic mirror achieved by nanostructuring a metal surface. In contrast to normal mirrors, it inflicts only small change to the phase of a reflected wave, offering intriguing applications.

Electromagnetic Wave Diffraction by Periodic Planar Metamaterials with Nonlinear Constituents

We present a theory which explains how to achieve an enhancement of nonlinear effects in a thin layer of nonlinear medium by involving a planar periodic structure specially designed to bear a trapped-mode resonant regime. In particular, the possibility of a nonlinear thin metamaterial to produce the bistable response at a relatively low input intensity due to a large quality factor of the trapped-mode resonance is shown. Also a simple design of an all-dielectric low-loss silicon-based planar metamaterial which can provide an extremely sharp resonant reflection and transmission is proposed. The designed metamaterial is envisioned for aggregating with a pumped active medium to achieve an enhancement of quantum dots luminescence and to produce an all-dielectric analog of a ‘lasing spacer’.

Two-oscillator model of trapped-modes interaction in a nonlinear bilayer fish-scale metamaterial

We discuss a similarity between resonant oscillations in two nonlinear systems; namely, a chain of coupled Duffing oscillators and a bilayer fish-scale metamaterial. In such systems two different resonant states arise which differ in their spectral lines. The spectral line of the first resonant state has a Lorentzian form, whereas the second one has a Fano form. This difference leads to a specific nonlinear response of the systems which manifests itself in the appearance of closed loops in spectral lines and bending and overlapping of resonant curves. Conditions for achieving bistability and multistability are determined.

Electromagnetic wave diffraction by plane periodic grating of wavy metal strips

A numerical solution of electromagnetic wave diffraction by a two-periodic grating of wavy metal strips placed on a dielectric substrate is obtained. The solution is verified for a particular case of straight strips by comparison with the rigorous solution. Frequency dependencies of reflection coefficients are analyzed. Differences from reflection from classical one-periodic gratings of straight strips are mentioned.

Fano resonances in two-layered planar nonlinear metamaterial with a fish scale structure

We report on a bistable light transmission through two-layered structure which consists of two gratings of planar perfectly conducting infinite strips placed on the both sides of a dielectric slab. It is demonstrated that a switching may be achieved nearly the frequency of the high-quality-factor Fano-shape trapped-mode resonance excitation.

Trapped mode resonances of metal-dielectric arrays

One-periodic planar arrays of straight wires or metal strips have a long history of applications as quasi-optical polarizing devices and partially transparent mirrors. Their properties are well known.