Andrey Novitsky

Elliptical dichroism: operating principle of planar chiral metamaterials

We employ a homogenization technique based on the Lorentz electronic theory to show that planar chiral structures (PCSs) can be described by an effective dielectric tensor similar to that of biaxial elliptically dichroic crystals. Such a crystal is shown to behave like a PCS insofar as it exhibits its characteristic optical properties, namely, corotating elliptical polarization eigenstates and asymmetric, direction-dependent transmission for left- or right-handed incident wave polarization.

Nonparaxial Airy beams: role of evanescent waves.

We report on the propagation dynamics of Airy light beams under nonparaxial conditions. The partial waves forming the Airy beam can be divided into two parts, the first of which contains only propagating waves, while the second part consists of evanescent waves. In this Letter we propose the concept of the evanescent Airy beam. We analyze the structure of the ideal evanescent Airy beam, the initial profile of which has the Airy form, while its spectral decomposition consists of only evanescent partial waves. Also, we discuss the refraction of the Airy beam through an interface and investigate the field of the transmitted Airy beam.

Electromagnetic interaction of arbitrary radial-dependent anisotropic spheres and improved invisibility for nonlinear-transformation-based cloaks

An analytical method of electromagnetic wave interactions with a general radially anisotropic cloak is established. It is able to deal with arbitrary parameters [ epsilon r (r) , mu r (r) , epsilon t (r) , and mu t (r) ] of a radially anisotropic inhomogeneous shell. The general cloaking condition is proposed from the wave relations, in contrast to the method of transformation optics. Spherical metamaterial cloaks with improved invisibility performance are achieved with optimal nonlinearity in transformation and core-shell ratio.

Transformation-based spherical cloaks designed by an implicit transformation-independent method: theory and optimization

Based on the concept of the cloak generating function, we propose an implicit transformation-independent method for the required parameters of spherical cloaks without knowing the needed coordinate transformation beforehand. A non-ideal discrete model is used to calculate and optimize the total scattering cross-sections of different profiles of the generating function. A bell-shaped quadratic spherical cloak is found to be the best candidate, which is further optimized by controlling the design parameters involved. Such improved invisibility is steady even when the model is highly discretized.

Inverse design mechanism of cylindrical cloaks without knowledge of the required coordinate transformation

An inverse way to define the parameters of cylindrical cloaks is developed, in which the cloaking parameters can be independently obtained without any knowledge of the corresponding coordinate transformation. The required parameters are derived in terms of the integral form of cloaking generators, which are very general and allow us to examine the significance of the parametric profiles. The validity of such inverse way and the invisibility characteristics are presented in full-wave numerical simulation of plane wave scattering by cloaked cylinders.

Engineering light-matter interaction for emerging optical manipulation applications

Abstract In this review, we explore recent trends in optical micromanipulation by engineering light-matter interaction and controlling the mechanical effects of optical fields. One central theme is exploring the rich phenomena beyond the now established precision measurements based on trapping micro beads with tightly focused beams. Novel synthesized beams, exploiting the linear and angular momentum of light, open new possibilities in optical trapping and micromanipulation. Similarly, novel structures are promising to enable new optical micromanipulation modalities. Moreover, an overview of the amazing features of the optics of tractor beams and backward-directed energy fluxes will be presented. Recently the so-called effect of negative propagation of the beams (existence of the backward energy fluxes) has been confirmed for X-waves and Airy beams. In the review, we will also discuss the negative pulling force of structured beams and negative energy fluxes in the vicinity of fibers. The effect is achieved due to the interaction of multipoles or, in another interpretation, the momentum conservation. Both backward-directed Poynting vector and backward optical forces are counter-intuitive and give an insight into new physics and technologies. Exploiting the degrees of freedom in synthesizing novel beams and designed microstructures offer attractive prospects for emerging optical manipulation applications.

Topological effects in anisotropy-induced nano-fano resonance of a cylinder.

We demonstrate that optical Fano resonance can be induced by the anisotropy of a cylinder rather than frequency selection under the resonant condition. A tiny perturbation in anisotropy can result in a giant switch in the principal optic axis near plasmon resonance. Such anisotropy-induced Fano resonance shows fast reversion between forward and backward scattering at the lowest-energy interference. The near and far fields of the particle change dramatically around Fano resonance. The topology of optical singular points and the trajectory of energy flux distinctly reveal the interaction between the incident wave and the localized surface plasmons, which also determine the far-field scattering pattern. The anisotropy-induced Fano resonance and its high sensitivity open new perspectives on light-matter interactions and promise potential applications in biological sensors, optical switches, and optomechanics.

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.

Light dynamics in PT-symmetric multilayers: Phase transition, nonreciprocity, and propagation direction locking

We report the numerical study of PT -symmetry breaking in one-dimensional structures with resonantly absorbing and amplifying layers described by the Maxwell-Bloch equations. Temporal dynamics of light interacting with such a structure is governed by strong field amplification and subsequent saturation of loss and gain above the exceptional point resulting in the lasing-like regime with powerful pulses generated both in reflection and transmission. In this regime, we predict and investigate the uniqueness of phase transition due to saturation, transmission nonreciprocity, and the direction locking of the transmitted and reflected radiation. Optical PT -symmetric structures and the effects connected to PT -symmetry breaking is one of the hot topics in modern photonics [1, 2, 3]. In one-dimensional (1D) geometry, optical PT -symmetric structure can be realized as a photonic-crystal-like system composed of alternating loss and gain layers. Such a multilayer should have proper spatial variation of the complex permittivity satisfying the necessary condition ε(z) = ε∗(−z), i.e., the real part of the permittivity is an even function of the coordinate, whereas the imaginary part is an odd function. There is a number of phenomena associated with violation of the PT symmetry, such as sharp change in polarization response of the system [4], enhanced sensitivity to external perturbations near exceptional point [5, 6], new effects of lasing [7, 8] and anti-lasing [9]. In this work, we consider a 1D structure in which both loss and gain materials are described as a two-level resonant medium. This allows us to describe self-consistently dynamics of field and material parameters and to shed new light on change of system’s temporal response at the exceptional point where the phase transition of PT -symmetry breaking occurs. The system considered in this work is a periodic planar structure composed of 2N alternating loss and gain layers. It is illuminated by normally incident monochromatic light of frequency ω. We describe both loss and gain in a similar manner, using the model of a homogeneously-broadened two-level