Plasmonic nanoresonators of core-shell composition and nanorod shape were optimized to tune their absorption cross-section maximum to the central wavelength of a short pulse. Their distribution along a pulse-length scaled target was optimized to maximize the absorptance with the criterion of minimal absorption difference in between neighbouring layers. Successive approximation of layer distributions made it possible to ensure almost uniform deposited energy distribution up until the maximal overlap of two counter-propagating pulses. Based on the larger absorptance and smaller uncertainty in absorptance and energy distribution core-shell nanoresonators override the nanorods. However, optimization of both nanoresonator distributions has potential applications, where efficient and uniform energy deposition is crucial, including phase transitions and even fusion.
Different types of concave plasmonic nanoresonators have been optimized to achieve superradiantly enhanced emission of SiV color centers in diamond. Comparative study has been performed to consider advantages of different N number of SiV color centers, different diamond-silver (bare) and diamond-silver-diamond (coated) core-shell nanoresonator types, as well as of spherical and ellipsoidal geometry. The complete fluorescence enhancement (qualified by Px factor) monitoring and the cQE corrected quantum efficiency weighted PxcQE objective function optimization promotes to design bad-cavities for…
Material losses in metals are a central bottleneck in plasmonics for many applications. Here we propose and theoretically demonstrate that metal losses can be successfully mitigated with dielectric particles on metallic films, giving rise to hybrid dielectric--metal resonances. In the far field, they yield strong and efficient scattering, beyond even the theoretical limits of all-metal and all-dielectric structures. In the near field, they offer high-Purcell-factor (${>}5000$), high-quantum-efficiency (${>}90\%$), and highly directional emission at visible and infrared wavelengths. Their quali…
The specificity of modal-expansion formalisms is their capabilities to model the physical properties in the natural resonance-state basis of the system in question, leading to a transparent interpretation of the numerical results. In electromagnetism, modal-expansion formalisms are routinely used for optical waveguides. In contrast, they are much less mature for analyzing open non-Hermitian systems, such as micro and nanoresonators. Here, by accounting for material dispersion with auxiliary fields, we considerably extend the capabilities of these formalisms, in terms of computational effective…
We theoretically study hot electron generation through the emission of a dipole source coupled to a nanoresonator on a metal surface. In our hybrid approach, we solve the time-harmonic Maxwell's equations numerically and apply a quantum model to predict the efficiency of hot electron generation. Strongly confined electromagnetic fields and the strong enhancement of hot electron generation at the metal surface are predicted and are further interpreted with the theory of quasinormal modes. In the investigated nanoresonator setup, both the emitting source and the acceptor resonator are localized …
We theoretically demonstrate the generation and radiation of coherent nanoplasmons powered by a single three-level quantum emitter on a plasmonic nanoresonator. By pumping the three-level emitter in a Raman configuration, we show a pathway to achieve macroscopic accumulation of nanoplasmons due to stimulated emission in the nanoresonator despite their fast relaxation. Thanks to the antenna effect of the nanoresonator, the system acts as an efficient and bright nanoscopic coherent light source with a photon emission rate of hundreds of Terahertz and could be realized with solid-state emitters a…
We derive a closed-form expression that accurately predicts the peak frequency-shift and broadening induced by tiny perturbations of plasmonic nanoresonators without critically relying on repeated electrodynamic simulations of the spectral response of nanoresonator for various locations, sizes or shapes of the perturbing objects. The force of the present approach, in comparison with other approaches of the same kind, is that the derivation is supported by a mathematical formalism based on a rigorous normalization of the resonance modes of nanoresonators consisting of lossy and dispersive mater…
Configuration of three different concave silver core-shell nanoresonators was numerically optimized to enhance the excitation and emission of embedded silicon vacancy (SiV) diamond color centers simultaneously. According to the tradeoff between the radiative rate enhancement and quantum efficiency (QE) conditional optimization was performed to ensure ~2-3-4 and 5-fold apparent cQE enhancement of SiV color centers with ~10% intrinsic QE. The enhancement spectra, as well as the near-field and charge distribution were inspected to uncover the physics underlying behind the optical responses. The c…
Plasmonic nanoresonators consisting of a gold nanorod and a spherical silica-core and gold-shell, both coated by a gain layer, were optimized to maximize the near-field enhancement (NF-type) and far-field outcoupling (FF-type), and to enter into the spasing operation region (NF-c*-type). It was shown that in case of moderate concentration the nanorod has more advantages: smaller lasing threshold, larger slope efficiency and achieved intensities in the near-field, in addition in FF-type system smaller gain and outflow threshold, earlier flipping and larger far-field out-coupling efficiency. How…
The plasmonic structures exhibiting narrowband resonances (NBR) are of a great interest for various applications. We propose to use hysteresis behavior in a 1D system of nonlinear nanoresonators in order to achieve the NRB; the nonlinearity is provided by saturation of a two-level quantum system coupled with the nanoresonators (nanolaser/spaser configuration). Quantum Dots (QD) were assumed as quantum systems; their numerical parameters have been adopted for estimations. Role of the loss compensation on the quality of the NBR is shown for below (under compensation) and above threshold (generat…
Electromagnetic cavity modes in photonic and plasmonic resonators offer rich and attractive regimes for tailoring the properties of light-matter interactions. Yet there is a disturbing lack of a precise definition for what constitutes a cavity mode, and as a result their mathematical properties remain largely unspecified. The lack of a definition is evidenced in part by the diverse nomenclature at use - "resonance", "leaky mode", "quasimode", to name but a few - suggesting that the dissipative nature of cavity modes somehow makes them different from other modes, but an explicit distinction is …
Nonlocal effects have been shown to be responsible for a variety of non-trivial optical effects in small-size plasmonic nanoparticles, beyond classical electrodynamics. However, it is not clear whether optical mode descriptions can be applied to such extreme confinement regimes. Here, we present a powerful and intuitive quasinormal mode description of the nonlocal optical response for three-dimensional plasmonic nanoresonators. The nonlocal hydrodynamical model and a generalized nonlocal optical response model for plasmonic nanoresonators are used to construct an intuitive modal theory and to …
Electron beam induced deposition (EBID) currently provides the only direct writing technique for truly three-dimensional nanostructures with geometrical features below 50 nm. Unfortunately, the depositions from metal-organic precursors suffer from a substantial carbon content. This hinders many applications, especially in plasmonics where the metallic nature of the geometric surfaces is mandatory. To overcome this problem a post-deposition treatment with oxygen plasma at room temperature was investigated for the purification of gold containing EBID structures. Upon plasma treatment, the struct…
Plasmonically enhanced fluorescence is a widely studied and applied phenomenon, however only a comparative theoretical and experimental analyses of coupled fluorophores and plasmonic nanoresonators makes it possible to uncover, how this phenomenon can be controlled. A numerical optimization method was applied to design configurations that are capable of resulting in an enhancement of excitation and emission, moreover of both phenomena simultaneously in coupled Cy5 dye molecule and gold nanorod systems. Parametric sensitivity studies revealed, how the fluorescence enhancement depends on the mol…
Sensing lower molecular weight in a diluted solution using a label-free biosensor is challenging and requires a miniaturized plasmonic structure, e.g., a vertical Au nanorod (AuNR) array based metamaterials. The sensitivity of a sensor mainly depends on transducer properties and hence for instance, the AuNR array geometry requires optimization. Physical vapour deposition methods (e.g., sputtering and e-beam evaporation) require a vacuum environment to deposit Au, which is costly, time-consuming, and thickness-limited. On the other hand, chemical deposition, i.e., electroplating deposit higher …
To integrate plasmonic devices into industry, it is essential to develop scalable and CMOS compatible plasmonic materials. In this work, we report high plasmonic quality titanium nitride (TiN) on c-plane sapphire by plasma enhanced atomic layer deposition (PE-ALD). TiN with low losses and high metallicity was achieved at temperatures below 500°C, by exploring the effects of chemisorption time, substrate temperature and plasma exposure time on material properties. Reduction in chemisorption time mitigates premature precursor decomposition at T_S > 375°C , and a trade-off between reduced impurit…
The present work addressed in this thesis introduces, for the first time, the use of tilted fiber Bragg grating (TFBG) sensors for accurate, real-time, and in-situ characterization of CVD and ALD processes for noble metals, but with a particular focus on gold due to its desirable optical and plasmonic properties. Through the use of orthogonally-polarized transverse electric (TE) and transverse magnetic (TM) resonance modes imposed by a boundary condition at the cladding-metal interface of the optical fiber, polarization-dependent resonances excited by the TFBG are easily decoupled. It was foun…
The plasmon resonances (modes) of a metal nanostructure can be defined as a dipole, a quadrupole, or high-order modes depending on the surface charge distribution induced by the incident field. In a non-symmetrical environment or clusters, the modes can hybridize and exhibit different behavior and properties. In this work, we study experimentally and numerically the substrate-induced hybridization of plasmonic modes of a silver nanocylinder. The applications of plasmonic nanoparticles such as refractive index sensing and enhanced spectroscopies often rely on the sustained mode spectral positio…
The determination of the chemical content is crucial for the quality control in high-precision device fabrication and advanced process development. For reliable chemical composition characterization, certain interaction volume of the target material is necessary for conventional techniques such as energy-dispersive X-ray spectroscopy (EDX) and electron energy loss spectroscopy (EELS). This remains however a challenge for nanostructures. We hereby propose an alternative technique for measuring chemical composition of nanostructures with limited volume. By measuring the differences in the optica…
Impact of Plasmonic Modes and Thermophysical Properties on the Double-Pulse Structuring of Highly-Ordered LIPSS for Biosensing Applications
Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology (FORTH)（电子结构与激光研究所，研究与技术基金会）；Department of Physics and Astronomy, Manchester University（曼彻斯特大学物理与天文学系）；Aix Marseille Univ, CNRS, LP3（艾克斯-马赛大学，法国国家科学研究中心，LP3）；Department of Physics, University of Crete（克里特大学物理系）
