arXiv subjects

Mária Csete

Publications and source records attributed to Mária Csete.

12 recordsLinked to original sources

arXiv2026

Multilayer Babinet metamaterial to initiate nonreciprocal topological phenomena and generalized Faraday rotation

Multilayers of Babinet complementary periodic structures constructed with miniarrays of spherical plasmonic nanoresonators were optimized to ensure Generalized Faraday Rotation. Nonreciprocal rotation and asymmetric transmission were achieved in spectrally overlapping regions due to the reach physics involving (i) symmetry breaking via coupled localized modes, (ii) Brillouin zone-folding stemmed from constituent sub-lattices forming in-plane twisted coupled loops, (iii) interlayer coupling between Babinet complementary patterns. The nanophotonical phenomena include (i) quasi-BIC resonances, (ii) hierarchically coupled localized and propagating modes that results in time-periodic Floquet modulation, (iii) initialization of synthetic potentials tuneable independently via intra and inter-layer parameters. The unique bianisotropic composites result in a synthetic vector gauge and emulated magnetic field manifesting itself in tilted-precessing magnetic dipoles and the accompanying modulation being time-periodic, inherently ensures a synthetic dimension. The asymmetric transmission is enhanced in the classical sense along quantized flat bands, and in mixed and forward bases inside finite wavelength-and-tilting intervals overlapping with nonreciprocal polarization rotation. The transmitted pulse re-shaping proves beating of nearby resonant modes, the loss can be compensated with active ad-layers thereby resulting in Faraday isolator capability. The multilayers synthetize topological phenomena in high-dimensional synthetic parameter spaces.

physics.optics↗

arXiv2026

Directed Nano-antennas for Laser Fusion

Why do we use nano-antennas for fusion? In three sentences: The present laser induced fusion plans use extreme mechanical shock compression to get one hotspot and then ignition. Still fusion burning spreads slower than expansion, and mechanical instabilities may also develop. With nano-antennas in radiation dominated systems, simultaneous ignition can be achieved in the whole target volume and there is no time left for mechanical instabilities. Ignition is achieved with protons accelerated in the direction of the nanoantennas that are orthogonal to the direction of laser irradiation. Present laser fusion methods are based on extreme and slow mechanical compression with an ablator surface on the fuel target pellet to increase compression and eliminate penetration of laser electromagnetic energy into the target. This arises from a mistaken assumption, [1] that the detonation normal 4-vector should have vanishing time-like component, and this assumption eliminates the possibility to rapid or even simultaneous, radiation dominated detonations, (which are well known in the burning (or hadronization) of Quark Gluon Plasma).

physics.plasm-ph↗

arXiv2024

Plasmonic structure integrated superconducting nanowire single-photon detector with BSCCO stripes

Superconducting nanowire single-photon detectors (SNSPDs) were integrated with plasmonic nanostructures to enhance the absorption efficiency of superconducting BSCCO stripes. A numerical investigation of optimized nanocavity array (NCAI) and nanocavity-trench-array (NCTAI) SNSPDs has revealed that more than one order of magnitude larger absorptance can be achieved at perpendicular incidence, when compared to the corresponding meandered BSCCO pattern in a resonant optical cavity. The SNSPDs were considerably improved either via first and third quarter cavity resonances, as evidenced by the near-field maps and validated by the standard retrieval method. Although, NCAI-SNSPD exhibits slightly larger absorptance, NCTAI-SNSPD remains competitive due to its larger period and significantly smaller filling factor, thereby allowing for quicker electric response.

physics.optics↗

arXiv2024

Layered Babinet complementary patterns acting as asymmetric negative index metamaterial

Azimuthal orientation and handedness dependence of the optical responses, accompanied by asymmetric transmission and asymmetric dichroism, were demonstrated on multilayers constructed with subwavelength periodic arrays of Babinet complementary miniarrays, illuminated by linearly and circularly polarized light. In case of single-sided illumination asymmetric optical responses were observed at the spectral location of maximal cross-polarization that is accompanied by radiative electric dipoles on the nano-objects; whereas negative index material phenomenon was demonstrated, where the electric and magnetic dipoles overlap both spatially and spectrally. The NIM is accompanied by electric multipoles that add up non-radiatively and correlates with the magnetic dipoles characteristic on the nano-entities. By illuminating the multilayer with two counter-propagating circularly polarized beams it was proven that asymmetrical normal component displacement currents at the bounding interfaces arising along flat and tilted bands accompany the asymmetric co-polarized and cross-polarized transmission, respectively. The latter correlates with the asymmetric dichroism in the cross-polarized signal observed in case of single-sided circularly polarized light illumination. The dispersion maps in the single-sided asymmetrical co-polarized reflectance and absorptance indicate flat bands of analogous and complementary extrema, proving the dichroic nature of the observed asymmetric phenomena. The multilayer is proposed as an ultrathin NIM and nonreciprocal nanophotonic element.

physics.optics↗

arXiv2024

PIC simulations of laser-induced proton acceleration by resonant nanoantennas for fusion

Rapid recent development in laser technology and methods learned from relativistic heavy ion physics led to new possibilities for fusion. Using a Hydrogen rich UDMA-TEGDMA polymer fusion target, laser irradiation ionizes the target. If we implant nanoantennas into the target resonating to the laser light frequency massive number of electrons of the ionized plasma resonate within the nanoantenna forming a so called nanoplasmonic wave. Our kinetic model simulation with a Hydrogen target indicates that the field of these resonating electrons attracts and accelerates the surrounding protons of the plasma to multi-MeV energy. These protons are then energetic enough to achieve nuclear transmutation and fusion reactions. Without resonating nanoantenna there is no such collective proton acceleration, no energetic protons, and nuclear reactions at 30 mJ laser pulse energy.

physics.plasm-ph↗

arXiv2024

Lasing and spasing with active individual core-shell plasmonic nanoresonators

Active core-shell nanoresonators were designed in order to achieve large near-field enhancement, large power-outflow and minimal spaser threshold in the pump E-field strength. Gain-metal-dielectric (GMD) and gain-metal-gain (GMG) nanoresonator compositions were optimized with corresponding objective functions. The average local E-field, power-outflow and extinction cross-section were mapped above the pump E-field strength and dye concentration parameter plane with the criterion that the local E-field is smaller than the damage threshold of the nanoresonator. Regions, corresponding to the maxima in the average local E-field, the highest power-outflow, or to the zero-crossing of the extinction cross-section, were selected for detailed studies. The spectral distribution of the near-field enhancement, optical cross-sections, optical responses, quantum efficiencies, as well as the polar angle distribution of the far-field radiated power and the local charge distribution of dominant modes were inspected. Based on the results the GMD nanoresonator composition is proposed to maximize local E-field in near-field amplifiers, to maximize power-outflow in far-field-emitting lasers and to minimize threshold E-field in spasers. Comparing the complete characteristics, both compositions are suitable for different operation regions, the GMG is proposed as near-field amplifier and far-field out-coupling nanolaser, whereas the GMD is unambiguously preferable to achieve optimal spaser properties.

physics.optics↗

arXiv2024

Plasmonic nanoprism distributions to promote enhanced and uniform energy deposition in passive and active targets

Passive and active targets, implanted with gold nanoprisms, were designed to achieve enhanced and uniform power absorption during two-sided illumination by short laser pulses. The target length was adjusted to match the short laser pulse-length. Capabilities of three different, uniform, single-peaked Gaussian and adjusted, nanoresonator number density distributions were compared. The average local E-field inside the gain medium and on the surface of the nanoprisms were mapped as a function of the pump E-field strength and dye concentration, assuming a uniform nanoresonator distribution. The optimal parameters were adopted to each inspected nanoprism distributions. The time-evolution of the near-field enhancement (NFE), integrated power-loss and deposited energy were determined, additionally, the time-evolution of the standard deviation of these quantities was monitored. A comparative study was performed on passive and active targets, to determine the most advantageous nanoprism number density distribution type and to consider the advantages of dye doping. Based on the results, the adjusted distribution is proposed both in passive and active targets. Doping with the dye is advantageous in every inspected distribution in decreasing the minimal standard deviation of the NFE. It is advantageous in decreasing the delay of the minimal standard deviation in the power-loss and deposited energy, the standard deviation of the NFE as well as in increasing the FOM of the NFE in the uniform and adjusted distributions. In addition, doping allows for decreasing the delay of the minimal standard deviation in the NFE / increasing the mean NFE / decreasing the standard deviation of the power-loss and deposited energy in the uniform / Gaussian / adjusted distribution.

physics.optics↗

arXiv2024

Solid and hollow plasmonic nanoresonators for carrier envelope phase read-out

The geometry of various plasmonic nanoantennae was numerically optimized to maximize their sensitivity to the carrier envelope phase (CEP) of the exciting ultra-short laser pulses. To verify the CEP sensitivity, the near-field response of the investigated nanoantennae was analyzed by combining frequency and time-domain numerical computations. The simulation methodology, capable of accurately calculating the time-dependent photocurrent stem from optical field emission, enabled the determination and optimization of all key parameters characterizing and governing the CEP dependence of the near-field responses. Three-types of structures were inspected, including individual triangular and teardrop-shaped nanoantennae and plasmonic lenses consisting of three hemispheres with gradually decreasing diameters. All structure types were optimized in solid and hollow compositions of gold nanoresonators as well. It was shown that hollow /solid singlets produce the largest /intermediate CEP dependent - to - CEP independent integrated current components' ratio, while their absolute CEP dependent integrated currents were the smallest /intermediate among the optimized structures. The highest /intermediate CEP sensitivity was achieved via solid plasmonic lenses due to their very large absolute CEP dependent integrated photocurrent originating from huge near-field enhancement in the nanogaps, while the integrated current components' ratio was smaller than for counterpart singlets.

physics.optics↗

arXiv2022

Kinetic Model Evaluation of Dynamical Properties of Nanaorod Antennas Embedded in a Polymer Carrying the Nuclei of Fusion Fuel

Recently laser induced fusion with simultaneous volume ignition, a spin-off from relativistic heavy ion collisions, was proposed, where implanted nanoantennas regulated and amplified the light absorption in the fusion target. Studies of resilience of the nanoantennas was published recently in vacuum. These studies are extended to nanoantennas embedded into a polymer, which modifies the nanoantenna's lifetime and absorption properties.

physics.plasm-ph↗

arXiv2021

Laser Wake Field Collider

Recently NAano-Plasmonic, Laser Inertial Fusion Experiments (NAPLIFE) were proposed, as an improved way to achieve laser driven fusion. The improvement is the combination of two basic research discoveries: (i) The possibility of detonations on space-time hyper-surfaces with time-like normal (i.e. simultaneous detonation in a whole volume) and (ii) to increase this volume to the whole target, by regulating the laser light absorption using nano-shells or nano-rods as antennas. These principles can be realized in an in-line, one dimensional configuration, in the simplest way with two opposing laser beams as in particle colliders. Such, opposing laser beam experiments were also performed recently. Here we study the consequences of the Laser Wake Field Acceleration (LWFA) if we experience it in a colliding laser beam set up. These studies can be applied to laser driven fusion, but also to other rapid phase transition, combustion, or ignition studies in other materials.

physics.plasm-ph↗

arXiv2017

Enhancing diamond fluorescence via optimized nanorod dimer configurations

Optical response of silicon (SiV) and nitrogen (NV) vacancy diamond color centers coupled to silver and gold nanorod dimers was numerically inspected. Optimization of the coupled emitter - nanorod dimer configurations was performed to attain the highest possible fluorescence enhancement by enhancing the excitation and emission of color centers simultaneously through plasmonic antenna resonances. To minimize losses conditional optimization was realized by setting a criterion regarding the minimum quantum efficiency of the coupled system (cQE). Restricted symmetric and allowed asymmetric antenna designs were also inspected to prove the potential advantages of asymmetric configurations tuneability. Among all inspected systems the highest 2.59*10^8 fluorescence enhancement with 46.08% cQE was achieved in case of NV color center coupled to asymmetric silver nanoantenna dimer. This is 3.17-times larger than the enhancement in corresponding symmetric configuration, which has larger 68.52% cQE. In case of SiV color center the highest 1.04*10^8 fluorescence enhancement with 37.83% cQE was achieved via asymmetric silver nanoantenna dimer. This is 1.06-times larger than the enhancement in the corresponding symmetric configuration, which has larger 57.46% cQE. The highest fluorescence enhancement achieved by gold nanorods is 4.75*10^4 with 21.8% cQE, which was shown in case of SiV color center coupled to asymmetric dimer. The attained enhancement is 8.48- (92.42-) times larger than the fluorescence enhancement achievable via symmetric (asymmetric) gold nanorod dimer coupled to SiV (NV) color center.

physics.optics↗

arXiv2011

Numerical method to optimize the Polar-Azimuthal Orientation of Infrared Superconducting Nanowire Single-Photon Detectors

A novel finite-element method for calculating the illumination-dependence of absorption in three-dimensional nanostructures is presented based on the RF module of the COMSOL software package. This method is capable of numerically determining the optical response and near-field distribution of sub-wavelength periodic structures as a function of illumination orientations specified by polar angle, fi, and azimuthal angle, gamma. The method was applied to determine the illumination-angle-dependent absorptance in cavity-based superconducting-nanowire single-photon detector (SNSPD) designs. Niobium-nitride stripes based on dimensions of conventional SNSPDs and integrated with ~ quarter-wavelength hydrogensilsesquioxane-filled nano-optical cavities and covered by a thin gold film acting as a reflector were illuminated from below by p-polarized light in this study. The numerical results were compared to results from complementary transfer-matrix-method calculations on composite layers made of analogous film-stacks. This comparison helped to uncover the optical phenomena contributing to the appearance of extrema in the optical response. This paper presents an approach to optimizing the absorptance of different sensing and detecting devices via simultaneous numerical optimization of the polar and azimuthal illumination angles.

physics.optics↗