arXiv subjects

Maxim A. Gorlach

Publications and source records attributed to Maxim A. Gorlach.

At least 37 records · Page 2Linked to original sources

arXiv2024

Observation of the magic angle and flat band physics in dipolar photonic lattices

Evanescently coupled waveguide arrays provide a tabletop platform to realize a variety of Hamiltonians, where physical waveguides correspond to the individual sites of a tight-binding lattice. Nontrivial spatial structure of the waveguide modes enriches this picture and uncovers further possibilities. Here, we demonstrate that the effective coupling between $p$-like modes of adjacent photonic waveguides changes its sign depending on their relative orientation vanishing for a proper alignment at a so-called magic angle. Using femtosecond laser-written waveguides, we demonstrate this experimentally for $p$-mode dimers and graphene-like photonic lattices exhibiting quasi-flat bands at this angle. We observe diffraction-free propagation of corner and bulk states providing a robust experimental evidence of a two-dimensional Aharonov-Bohm-like caging in an optically switchable system.

physics.optics↗

arXiv2024

Effective chiral response of anisotropic multilayered metamaterials

We consider a multilayered metamaterial composed of anisotropic layers with in-plane anisotropy axes periodically rotated with respect to each other. Due to the breaking of inversion symmetry, the structure develops an effective chirality. We derive the effective chirality tensor of the metamaterial describing both normal and oblique incidence scenarios. We also identify the arrangement of the layers maximizing chiral response for the fixed lattice period, wavelength and anisotropy of the layers.

physics.optics↗

arXiv2024

Dual origin of effective axion response

Effective axion fields in condensed matter and photonics are manifested as $\mathcal{P}$- and $\mathcal{T}$-odd contributions to the electromagnetic response. Here, we show that the phenomena previously attributed to the effective axion fields have two distinct physical origins. One of them corresponds to the standard axion electrodynamics, while another provides its dual-symmetric version having the same symmetry and featuring similar but distinguishable optical properties. We present an example system described by the dual-symmetric modification of axion electrodynamics, derive the key predictions and pinpoint experimentally observable distinctions between the two versions of axion-type response.

hep-ph↗

arXiv2024

Non-Hermitian excitations in nonlinear topological lattice

Non-linear effects and non-Hermitian phenomena unveil additional intricate facets in topological matter physics. They can naturally intertwine to enable advanced functionalities in topoelectrical circuits and photonic structures. Here, we illustrate the subtle interplay between nonlinearity and non-Hermiticity by examining the characteristics of small wave perturbations on the background of the self-induced topological edge state in the nonlinear Su-Schrieffer-Heeger model. We demonstrate that their underlying physics is captured by the non-Hermitian effective Hamiltonian, which features nonreciprocal coupling terms and entails unconventional time-dependent field localization.

physics.optics↗

arXiv2024

Probing ultrafast magnetization dynamics via synthetic axion fields

Spatial structuring of materials at subwavelength scales underlies the concept of metamaterials possessing exotic properties beyond those of the constituent media. Temporal modulation of material parameters enables further functionalities. Here, we show that high-frequency oscillations of spatially uniform magnetization generate an effective dynamic axion field embedding the amplitude and phase of magnetization oscillations. This allows one to map ultrafast magnetization dynamics using a probe signal with much lower frequency.

physics.optics↗

arXiv2023

Crafting crystalline topological insulators via accidental mode degeneracies

Crystalline topological insulators have recently become a powerful platform for realizing photonic topological states from microwaves to the visible. Appropriate geometric symmetries of the lattice are at the core of their functionality. Here we put forward an alternative approach to craft those systems by designing the internal symmetries of the Hamiltonian via accidental mode degeneracies. We illustrate our approach constructing ananalog of breathing honeycomb lattice using simpler lattice geometry and six times less meta-atoms, reveal edge and corner states and calculate the relevant topological invariants.

physics.optics↗

arXiv2023

Photonic molecule approach to multi-orbital topology

The concepts of topology provide a powerful tool to tailor the propagation and localization of light. While electromagnetic waves have only two polarization states, engineered degeneracies of photonic modes provide novel opportunities resembling orbital or spin degrees of freedom in condensed matter. Here, we tailor such degeneracies for the array of femtosecond laser written waveguides in the optical range exploiting the idea of photonic molecules -- clusters of strongly coupled waveguides. In our experiments, we observe the emergence of topological modes caused by the inter-orbital coupling and track multiple topological transitions in the system with the change of the lattice spacings and excitation wavelength. This strategy opens an avenue in designing novel types of photonic topological phases and states.

physics.optics↗

arXiv2023

Axion electrodynamics without Witten effect in metamaterials

Artificial media provide unique playground to test fundamental theories allowing one to probe the laws of electromagnetism in the presence of hypothetical axions. While some materials are known to realize this physics, here we propose the nonlocal extension of axion electrodynamics. Compared to the usual axion case, the suggested metamaterial features similar optical properties including Kerr and Faraday rotation. However, the external sources in this structure do not induce dyon charges eliminating well-celebrated Witten effect. We put forward the design of such nonreciprocal non-local metamaterial and discuss its potential applications.

physics.optics↗

arXiv2023

Tunable Wire Metamaterials for an Axion Haloscope

Metamaterials based on regular two-dimensional arrays of thin wires have attracted renewed attention in light of a recently proposed strategy to search for dark matter axions. When placed in the external magnetic field, such metamaterials facilitate resonant conversion of axions into plasmons near their plasma frequency. Since the axion mass is not known a priori, a practical way to tune the plasma frequency of metamaterial is required. In this work, we have studied a system of two interpenetrating rectangular wire lattices where their relative position is varied. The plasma frequency as a function of their relative position in two dimensions has been mapped out experimentally, and compared with both a semi-analytic theory of wire-array metamaterials and numerical simulations. Theory and simulation yield essentially identical results, which in turn are in excellent agreement with experimental data. Over the range of translations studied, the plasma frequency can be tuned over a range of 16%.

hep-ex↗

arXiv2023

Emergent axion response in multilayered metamaterials

We consider the design of metamaterials whose behavior embodies the equations of axion electrodynamics. We derive an effective medium description of an assembly of magneto-optical layers with out-of-plane magnetization analytically and show how to achieve effective axion response with tunable parameters. We display some key predictions and validate them numerically.

physics.optics↗

arXiv2022

Multipole higher-order topology in a multimode lattice

The concepts of topology have a profound impact on physics research spanning the fields of condensed matter, photonics and acoustics and predicting topological states that provide unprecedented versatility in routing and control of waves of various nature. Higher-order topological insulators further expand this plethora of possibilities towards extended range of structure dimensionalities. Here, we put forward a novel class of two-dimensional multipolar higher-order topological insulators that arise due to the interference of the degenerate modes of the individual meta-atoms generalizing the mechanism of spin-orbit coupling in condensed matter systems. We prove that this model features disorder-robust corner modes and cannot be reduced to the known crystalline topological phases or conventional quadrupole insulators, providing the first example of multipolar topology in a $C_3$-symmetric lattice featuring quantized octupole moment. The multimode nature of the lattice gives rise to flat bands and corner states with extreme localization enabling coherent control of the topological modes. We support our predictions by assembling the designed structure, observing multipolar topological corner states and experimentally demonstrating their coherent control.

physics.optics↗

arXiv2022

Coherent control of topological states in an integrated waveguide lattice

Topological photonics holds the promise for enhanced robustness of light localization and propagation enabled by the global symmetries of the system. While traditional designs of topological structures rely on lattice symmetries, there is an alternative strategy based on accidentally degenerate modes of the individual meta-atoms. Using this concept, we experimentally realize topological edge state in an integrated optical nanostructure based on the array of silicon nano-waveguides, each hosting a pair of degenerate modes at telecom wavelengths. Exploiting the hybrid nature of the topological mode formed by the superposition of waveguide modes with different symmetry, we implement coherent control of the topological edge state by adjusting the phase between the degenerate modes and demonstrating selective excitation of bulk or edge states. The resulting field distribution is imaged via third harmonic generation allowing us to quantify the localization of topological modes as a function of the relative phase of the excitations. Our results highlight the impact of engineered accidental degeneracies on the formation of topological phases, extending the opportunities stemming from topological nanophotonic systems.

physics.optics↗

arXiv2022

Effective Medium Perspective on Topological Transitions in Metamaterials

Many properties of photonic structures rely on band topology characterized by the integer invariants that can change during the topological transitions and give rise to the disorder-robust topological edge, corner, or interface states. Typically the periods of such structures are comparable to the wavelength. However, in many cases, the unit cell becomes deeply subwavelength and hence the entire metamaterial can be described in terms of the effective material parameters. Here, focusing on subwavelength topological metamaterials, we identify the behavior of permittivity and permeability accompanying the topological transition on the example of the two structures possessing $D_6$ symmetry.

physics.app-ph↗

arXiv2022

Reconfigurable topological states in arrays of bianisotropic particles

Topological photonics promotes a novel approach to resilient light manipulation by exploiting spatio-temporal symmetries of the system and dual symmetry of electromagnetic field. Various prospective device applications pose the need to flexibly control robust field localization associated with topological modes. Here we design a topological array of resonant dielectric meta-atoms with bianisotropic response induced by a spatial symmetry reduction. Mutual orientation of the designed meta-atoms encodes a staggered bianisotropy pattern capable of trapping topological states in a one-dimensional array containing a small number of particles. We show that the topological interface state can be tailored by the rotation of coaxial bianisotropic particles arranged in an equidistant lattice. Our experimental implementation based on ceramic horseshoe-shaped disks demonstrates remarkable reconfigurability of electromagnetic topological states.

physics.app-ph↗

arXiv2021

Tailoring higher-order topological phases via orbital hybridization

Higher-order topological insulators (HOTIs) have attracted much attention in photonics due to the tightly localized disorder-robust corner and hinge states. Here, we reveal an unconventional HOTI phase with vanishing dipole and quadrupole polarizations. This phase arises in the array of evanescently coupled waveguides hosting degenerate $s$- and $d$-type orbital modes arranged in a square lattice with four waveguides in the unit cell. As we prove, the degeneracy of the modes with the different symmetry gives rise to the nontrivial topological properties rendering the system equivalent to the two copies of anisotropic two-dimensional Su-Schrieffer-Heeger model rotated by 90$^\circ$ with respect to each other and based on $s\pm d$ hybridized orbitals. Our results introduce a route to tailor higher-order band topology leveraging both crystalline symmetries and accidental degeneracies of the different orbital modes.

physics.optics↗

arXiv2021

Electric circuit emulation of topological transitions driven by quantum statistics

Topological phases exhibit a plethora of striking phenomena including disorder-robust localization and propagation of waves of various nature. Of special interest are the transitions between the different topological phases which are typically controlled by the external parameters. In contrast, in this Letter, we predict the topological transition in the two-particle interacting system driven by the particles' quantum statistics. As a toy model, we investigate an extended one-dimensional Hubbard model with two anyonic excitations obeying fractional quantum statistics in-between bosons and fermions. As we demonstrate, the interplay of two-particle interactions and tunneling processes enables topological edge states of anyon pairs whose existence and localization at one or another edge of the one-dimensional system is governed by the quantum statistics of particles. Since a direct realization of the proposed system is challenging, we develop a rigorous method to emulate the eigenmodes and eigenenergies of anyon pairs with resonant electric circuits.

quant-ph↗

arXiv2021

Higher-order topological phase induced by hybrid magneto-electric resonances

Rapid development of topological concepts in photonics unveils exotic phenomena such as unidirectional propagation of electromagnetic waves resilient to backscattering at sharp bends and disorder-immune localization of light at stable frequencies. Recently introduced higher-order topological insulators (HOTIs) bring in additional degrees of control over light confinement and steering. However, designs of photonic HOTIs reported so far are solely exploiting lattice geometries which are hard to reconfigure thus limiting tunability. Here, we elaborate a conceptually new mechanism to engineer higher-order topological phases which relies on the dual nature of electromagnetic field and exploits both electric and magnetic responses of the meta-atoms. Hybridization between these responses gives rise to the difference in the effective coupling which is controlled by the meta-atoms mutual orientations. This feature facilitates us to tailor photonic band topology exclusively via particle alignment and to flexibly reconfigure the topological phase. Focusing on the kagome array of split-ring resonators, we experimentally demonstrate topological edge and corner states in the microwave domain. Our findings provide a new promising route to induce and control higher-order topological phases and states.

cond-mat.mes-hall↗

arXiv2021

Three-dimensional higher-order topological insulator protected by cubic symmetry

Recently discovered photonic higher-order topological insulators enable unprecedented flexibility in the robust localization of light in structures of different dimensionality. While the potential of the two-dimensional systems is currently under active investigation, only a few studies explore the physics of the three-dimensional higher-order topological insulators. Here we propose a three-dimensional structure with cubic symmetry exhibiting vanishing bulk polarization but nonzero corner charge and hosting a zero-dimensional corner state mediated by the long-range interactions. We trace the evolution of the corner state with the next-nearest-neighbor coupling strength and prove the topological origin of the corner mode calculating the associated topological invariants. Our results thus reveal the potential of long-range couplings for the formation of three-dimensional higher-order topological phases.

cond-mat.mes-hall↗