Mr. Krzysztof M. Czajkowski Profile

Krzysztof M. Czajkowski

at Univ of Warsaw

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Author

Publications (6)

Proceedings Article | 24 May 2022 Presentation + Paper

Chirality enhancement in substrate supported nanostructures

Krzysztof Czajkowski, Tomasz Antosiewicz

Proceedings Volume 12130, 1213005 (2022) https://doi.org/10.1117/12.2624378

KEYWORDS: Particles, Dichroic materials, Molecules, Scattering, Nanostructures, Optical spheres, Light scattering, Refractive index, Absorption, Multiple scattering

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Proceedings Article | 24 May 2022 Poster + Presentation + Paper

Optical properties of hyperbolic nanoresonators

Maria Bancerek, Krzysztof Czajkowski, A. Korneluk, D. Świtlik, Tomasz Antosiewicz

Proceedings Volume 12130, 121300K (2022) https://doi.org/10.1117/12.2624422

KEYWORDS: Magnetism, Optical properties, Metals, Resonators, Polarization, Dispersion, Metamaterials, Energy efficiency, Dielectrics

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Hyperbolic metamaterials (HMMs) gained a lot of interest amongst researchers in recent years due to their novel properties stemming from hyperbolic dispersion, such as anomalous scattering, subwavelength confinement of light or enhancing far-field radiation. In our work, we investigate optical properties of nanostructured HMMs in a form of spherical nanoresonators composed of stacked alternating metal-dielectric layers, which is one way to realize hyperbolic dispersion. Using T-matrix analysis, combined with a quasistatic approach, we explore their unique spectral response to unravel fundamental electromagnetic properties of hyperbolic nanoresonators. The modal structure of hyperbolic nanospheres (HNSs) is richer than those of conventional nanoantennas and can be tuned either with material properties or incident light conditions. We show that, depending on the direction and polarization of incident light, such nanoresonators can exhibit a plasmonic-like response or one with an atypical modal order, with electric and magnetic modes of higher orders appearing at energies below those of lower order modes. We underline how constructive or destructive cross coupling between various electric and magnetic multipoles, determined by the hyperbolic dispersion, influences the overall optical response and enables phenomena absent in the isotropic medium. Such an example is a negative contribution of a given mode to the extinction cross-section, stemming from destructive cross coupling and is an indicator of energy transfer between modes. We show how mode cross coupling (and thus HNS optical properties) change with material properties – varying the metal fill-factor allows for significant tunability from a uniaxial dielectric through a type I or II hyperbolic material to a uniaxial metal. By applying the quasistatic approach we also analyse the origin of the dipolar modes and obtain material-dependent resonance conditions for both electric and magnetic mode. Furthermore, we conclude that magnetic dipolar resonance presence is determined by the hyperbolic disperison, i.e. opposite signs of the ordinary and extraordinary permittivities.

Proceedings Article | 18 April 2021 Presentation + Paper

Substrate-supported dielectric arrays for refractometric sensing purposes

Maria Bancerek, Krzysztof Czajkowski, Olga Kochanowska, Tomasz Antosiewicz

Proceedings Volume 11769, 117690D (2021) https://doi.org/10.1117/12.2592434

KEYWORDS: Dielectrics, Silicon, Magnetism, Refractive index, Particles, Optical components, Nanophotonics, Nanoantennas, Multiple scattering, Electromagnetic coupling

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Proceedings Article | 18 April 2021 Presentation + Paper

Far-field optical properties of disordered dielectric nanoparticle arrays within T-matrix framework

Krzysztof Czajkowski, Maria Bancerek, T. Antosiewicz

Proceedings Volume 11769, 1176905 (2021) https://doi.org/10.1117/12.2591853

KEYWORDS: Nanoparticles, Optical properties, Dielectrics, Multiple scattering, Light scattering, Scattering, Photovoltaics

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Proceedings Article | 30 April 2019 Presentation + Paper

Electric and magnetic dipole and quadrupole coupling in an effective medium description of amorphous arrays of optical nanoresonators

Krzysztof Czajkowski, Tomasz Antosiewicz

Proceedings Volume 11025, 110250S (2019) https://doi.org/10.1117/12.2522773

KEYWORDS: Nanoparticles, Magnetism, Refractive index, Polarizability, Particles, Mie scattering, Plasmonics, Silicon, Silver, Disordered photonic crystals

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The optical properties of spherical nanoparticles are described by Mie theory which yields their multipole electric and magnetic resonances. Their characteristics (and presence) depend on nanoparticle size and material. For sufficiently small metallic nanoparticles the response is determined by the electric dipolar polarizability in the small particle limit. However, as the size increases, higher order electric multipoles have to be accounted for. Although, not particularly strong, the magnetic response of metallic nanoparticles can also lead to significant optical effects when the nanoparticle is placed in an array. It is, however, significantly stronger in dielectric nanoparticles due to circular displacement current of the electric field. The orientation of the induced magnetic dipole is perpendicular to that of the corresponding electric dipole. As in the case of metallic nanoparticles higher order multipoles have to be considered. This work focuses on amorphous arrays of nanoparticles in which the nanoparticles are placed randomly using a random sequential adsorption algorithm (RSA) with the condition that a minimum center-to-center distance (lcc) between the nanoparticles is present, lcc=CCxD, where D is the nanoparticle diameter and CC is a dimensionless parameter. For simplicity it is assumed that all the nanoparticles have the same diameter. Building upon previous work, we develop a framework in which a localized optical mode of an amorphous array of discrete nanoparticles is self-consistently calculated by assuming that, on average, the nanoparticle is excited by the same field consisting of the incident field and the average scattered field from all the other particles in the system. In this work, this approach is extended to include higher order modes as well as those of the magnetic character. First, the extinction cross-section spectra for dielectric spherical nanoparticles are analyzed as a function of size in terms of contributions from various multipoles. Then, the effective medium description of amorphous arrays of nanoparticles is presented and supported by numerical calculations with T-Matrix method.

Proceedings Article | 30 April 2019 Presentation + Paper

Subwavelength confinement of light in hyperbolic metamaterials with dielectric nanoparticle coupling

Krzysztof Czajkowski, Maria Bancerek, Tomasz Antosiewicz, Rafał Kotyński

Proceedings Volume 11025, 110250D (2019) https://doi.org/10.1117/12.2522771

KEYWORDS: Computational imaging, Super resolution, Metamaterials, Nanoparticles, Dielectrics, Interfaces, Metals, Light wave propagation, Diffraction, Dispersion

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Showing 5 of 6 publications

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