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Modal analysis for nanoplasmonics with nonlocal material properties
摘要： Plasmonic devices with feature sizes of a few nanometers exhibit effects which can be described by the nonlocal hydrodynamic Drude model. We demonstrate how to exploit contour integral methods for computing eigenfrequencies and resonant states of such systems. We propose an approach for deriving the modal expansion of relevant physical observables. We use the methods to perform a modal analysis for a metal nanowire. All complex eigenfrequencies in a large frequency range and the corresponding resonant states are computed. We identify those resonant states which are relevant for the extinction cross section of the nanowire.
关键词： extinction cross section,nanoplasmonics,hydrodynamic Drude model,modal analysis,nonlocal material properties,metal nanowire
更新于2025-09-16 10:30:52
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Chemical Nanoplasmonics: Emerging Interdisciplinary Research Field at Crossroads between Nanoscale Chemistry and Plasmonics
摘要： Plasmonics research deals with understanding and manipulating the interaction between light and matter at a scale that is significantly smaller than the wavelength of light (e.g., metal nanoparticles). Such an interaction can be correlated with various forms of energy and signals such as thermal energy and optical spectra. Research efforts in plasmonics range from rationally designing and precisely synthesizing nanostructures that allow for unraveling and reliably tuning novel and useful plasmonic properties (e.g., surface-enhanced spectroscopies and photothermal effects) to ultimately obtaining and utilizing plasmonic functionalities for applications, for example, in the biomedical field. With enormous potential and versatility in terms of plasmonic materials and devices, the principles of plasmonics are expected to provide new or improved solutions to many important challenges in various subfields of chemistry, including nanoparticle chemistry, catalytic reactions, surface-enhanced Raman scattering, photovoltaics, sensing, biochemistry, and therapeutics. Additionally, many hurdles and issues related to the advances and applications of plasmonics can be addressed by material- or property-based chemistry at the nanoscale (i.e., nanochemistry), while chemical principles and methods can offer new research directions in plasmonics. Nanochemistry allows scientists to develop exquisitely accurate methods for the synthesis of nanostructures with high precision and provides tools for functionalizing and analyzing complex plasmonic nanostructures (e.g., heterostructured-nanoparticles). Therefore, recent advancements in nanochemistry with plasmonic materials have made a great impact on the proper use and real applications of plasmonics, and plasmonics offers in turn new pathways and tools for chemical processes. The field of chemical nanoplasmonics includes the study of nanoscale chemistry for the advancement of plasmonics and the use of plasmonics to address key issues and challenges in chemistry. Newly emerging principles, methods, and materials in plasmonics can be useful in various fields of chemistry, including optical and chemical hot spots, typically based on strong electromagnetic fields formed within plasmonic nanostructures, as well as single-molecule and 3D SERS with plasmonic hot-spot platforms. Plasmonic multimers (e.g., gold nanoparticle dimers), plasmonic supercrystals, plasmonic nanoparticle lattices, gold nanobipyramids, virus-sized gold nanorods, spherical nucleic acids, plasmonic metamaterials, and chiral plasmonic structures are some of the key nanostructures for materials chemistry-based plasmonics. Hot charge carriers and plasmon-driven catalysis have been identified as important directions for many subfields of chemistry including physical chemistry, materials chemistry, and catalysis. Further, newly emerging platforms such as plasmonic nanoparticle-interfaced cell membranes, DNA origami-based plasmonics, and graphene-based nonlinear plasmonics have emerged as next-generation platforms that can provide new ways of forming functional materials and devices, including optical and computing devices.
关键词： photovoltaics,plasmonics,nanochemistry,biochemistry,nanoplasmonics,sensing,surface-enhanced Raman scattering,therapeutics
更新于2025-09-12 10:27:22
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Rapid and Digital Detection of Inflammatory Biomarkers Enabled by a Novel Portable Nanoplasmonic Imager
摘要： New point-of-care diagnostic devices are urgently needed for rapid and accurate diagnosis, particularly in the management of life-threatening infections and sepsis, where immediate treatment is key. Sepsis is a critical condition caused by systemic response to infection, with chances of survival drastically decreasing every hour. A novel portable biosensor based on nanoparticle-enhanced digital plasmonic imaging is reported for rapid and sensitive detection of two sepsis-related inflammatory biomarkers, procalcitonin (PCT) and C-reactive protein (CRP) directly from blood serum. The device achieves outstanding limit of detection of 21.3 pg mL?1 for PCT and 36 pg mL?1 for CRP, and dynamic range of at least three orders of magnitude. The portable device is deployed at Vall d’Hebron University Hospital in Spain and tested with a wide range of patient samples with sepsis, noninfectious systemic inflammatory response syndrome (SIRS), and healthy subjects. The results are validated against ultimate clinical diagnosis and currently used immunoassays, and show that the device provides accurate and robust performance equivalent to gold-standard laboratory tests. Importantly, the plasmonic imager can enable identification of PCT levels typical of sepsis and SIRS patients in less than 15 min. The compact and low-cost device is a promising solution for assisting rapid and accurate on-site sepsis diagnosis.
关键词： imaging biosensors,nanoplasmonics,point-of-care diagnostics,sepsis,gold nanoparticles
更新于2025-09-12 10:27:22
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Nanoplasmonic 1D Diamond UV Photodetectors with High Performance
摘要： Diamond nanowires have recently drawn substantial attention due to their unique physical and chemical properties for electrochemical sensors, optoelectronics, and nanophotonics applications. However, diamond nanowire based ultraviolet photodetectors have not been reported because of the challenges involved in synthesizing crystalline diamond nanowires with controllable morphologies and, more fundamentally, the material’s high carrier concentration with low mobilities that limits the obtainable photoresponsivity. The synergetic integration of ultrananocrystalline diamond (UNCD) nanowires with nanoplasmonic enhancement by noble metal nanoparticles is a very promising approach to overcome these shortcomings. Here we report the fabrication of boron doped ultrananocrystalline diamond nanowires functionalized with the platinum nanoparticles to form self-powered ultraviolet photodetectors that exhibit an ultrahigh photoresponsivity of 388 Amp/Watt at 300 nm wavelength, a fast response time around 20 ms, and a good UV/visible rejection ratio of about five orders of magnitude under zero-bias condition.
关键词： ultraviolet photodetector,nanowire,metal nanoparticle,ultrananocrystalline diamond,nanoplasmonics
更新于2025-09-12 10:27:22
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Applied Nanophotonics || Lightwaves in restricted geometries
摘要： The subject of this chapter is propagation, reflection, and evanescence of electromagnetic waves in continuous and complex media and structures to introduce the basics of wave optics and its implementation in novel nanophotonic conceptions. Electromagnetic waves propagate in a medium with positive permittivity, reflect at every permittivity step, and evanesce in a metal featuring negative permittivity. Combination of different dielectrics allows for wave confinement, tunneling, and energy storage, and gives rise to the photonic crystals notion. Combination of a metal with a dielectric material in nanostructures allows for optical material design like stained glass and very high local concentration of incident field to arrive at the notion of nanoplasmonics and optical antennas.
关键词： wave optics,photonic crystals,optical antennas,nanophotonics,electromagnetic waves,nanoplasmonics
更新于2025-09-09 09:28:46
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Applied Nanophotonics || Emerging nanophotonics
摘要： In this chapter a number of challenging trends in modern nanophotonics are highlighted that can be traced based on extensive research during the last decades. These are the colloidal technological platform, nanoplasmonics to enhance light–matter interaction, novel optical sensors based on nanostructures, advances toward the silicon photonic platform, negative refractive index materials, and single photon emitters. These novel trends and ideas, when seen together, provide a definite forecast for new exciting devices and systems to appear in the next decades and present nanophotonics as an extremely active and promising field of research and development.
关键词： silicon photonic platform,optical sensors,colloidal technological platform,negative refractive index materials,nanophotonics,single photon emitters,nanoplasmonics
更新于2025-09-09 09:28:46
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Label-free bacteria quantification in blood plasma by a bioprinted microarray based interferometric point-of-care device
摘要： Existing clinical methods for bacteria detection lack in speed, sensitivity and importantly in Point-of-Care (PoC) applicability. Thus, finding ways to push the sensitivity of clinical PoC biosensing technologies is crucial. Aiming that, we here report a portable PoC device based on Lens-free Interferometric Microscopy (LIM). The device employs high performance nanoplasmonics and custom bioprinted microarrays and is capable of direct label-free bacteria (E. coli) quantification. With only one-step sample handling we offer a sample?to?data turnaround time of 40 minutes. Our technology features detection sensitivity of a single bacterial cell both in buffer and diluted blood plasma and is intrinsically limited by the number of cells present in the detection volume. When employed in a hospital setting, the device has enabled accurate categorization of sepsis patients (infectious SIRS) from control groups (healthy individuals and non-infectious SIRS patients) without false positives/negatives. User-friendly on-site bacterial clinical diagnosis can thus become a reality.
关键词： microarray,label-free detection,plasma samples,nanoplasmonics,sepsis,bacteria
更新于2025-09-09 09:28:46
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Scattering characteristics of an exciton-plasmon nanohybrid made by coupling a monolayer graphene nanoflake to a carbon nanotube
摘要： A hybrid nanostructure where a graphene nanoflake (GNF) is optically coupled to a carbon nanotube (CNT) could potentially possess enhanced sensing capabilities compared to the individual constituents whilst inheriting their high biocompatibility, favourable electrical, mechanical and spectroscopic properties. Therefore, in this paper, we investigate the scattering characteristics of an all-carbon exciton-plasmon nanohybrid which was made by coupling an elliptical GNF resonator to a semiconducting CNT gain element. We analytically model the nanohybrid as an open quantum system using cavity quantum electrodynamics. We derive analytical expressions for the dipole moment operator and the dipole response field of the GNF and characterize the Rayleigh scattering spectrum of the nanohybrid. These analytical expressions are valid for any arbitrary ellipsoidal nanoresonator coupled to a quantum emitter. Furthermore, we perform a detailed numerical analysis, the results of which indicate that the GNF-CNT nanohybrid exhibits enhanced and versatile scattering capabilities compared to the individual constituents. We show that the spectral signatures of the nanohybrid are highly tunable using a multitude of system parameters such as Fermi energy of the GNF, component dimensions, GNF-CNT separation distance and the permittivity of the submerging medium. We finally demonstrate the prospect of using the proposed nanohybrid to reconstruct the permittivity profile of a tumour. The high biocompatibility and high sensitivity to the dielectric properties of the environment make the proposed GNF-CNT nanohybrid an ideal candidate for such biosensing applications.
关键词： cavity QED analysis,scattering,nanoplasmonics
更新于2025-09-09 09:28:46