The application of gold nanostars in direct and indirect surface-enhanced raman spectroscopy (SERS) sensing has significantly grown the past few years, mainly because particles' excellent field enhancement properties. However, experimental demonstrations correlating SERS signal enhancements to specific morphology features are still scarce, primarily complexity nanostar itself. Herein, we have addressed this fundamental issue by synthesizing surfactant-free nanostars, coating them with a...

A combined experimental and computational study was carried out to design a semi-empirical method determine the volume, surface area, extinction coefficients of gold nanostars. The values obtained were confirmed by reconstructing nanostar 3D topography through high-tilt TEM tomography introducing finite elements in COMSOL Multiphysics which we have also calculated morphology-dependent coefficient. Doing so, have, for first time, modeled heat losses real, experimentally synthesized nanostar,...

Abstract Reconfigurable metalenses are compact optical components composed by arrays of meta-atoms that offer unique opportunities for advanced systems, from microscopy to augmented reality platforms. Although poorly explored in the context reconfigurable metalenses, thermo-optical effects resonant silicon nanoresonators have recently emerged as a viable strategy realize tunable meta-atoms. In this work, we report proof-of-concept design an ultrathin (300 nm thick) and thermo-optically...

Single-walled carbon nanotubes (SWCNTs) emit near-infrared (NIR) fluorescence that is ideal for optical sensing. However, the low quantum yields diminish sensor's signal-to-noise ratio and limits penetration depths in vivo measurements. In this study, we perform a systematic investigation of plasmonic effects Ag Au nanoparticles various geometries to tune even enhance intensity single-stranded DNA-wrapped SWCNTs (ssDNA-SWCNTs). We observe chirality-dependent NIR enhancement varies with both...

Abstract Luminescence constitutes a unique source of insight into hot carrier processes in metals, including those plasmonic nanostructures used for sensing and energy applications. However, being weak nature, metal luminescence remains poorly understood, its microscopic origin strongly debated, potential unraveling nanoscale dynamics largely unexploited. Here, we reveal quantum-mechanical effects the emanating from thin monocrystalline gold flakes. Specifically, present experimental...

Gold nanostars display exceptional field enhancement properties and tunable resonant modes that can be leveraged to create effective imaging tags, phototherapeutic agents, hot electron-based photocatalytic platforms. Despite having emerged as the cornerstone among plasmonic nanoparticles with respect strength tunability, some well-known limitations have hampered their technological implementation. Herein we tackle these recognized intrinsic weaknesses, which stem from complex, thus...

Abstract Dielectric nanoresonators uniquely support both magnetic and electric resonances across a wide wavelength range. They are thus being exploited in growing number of groundbreaking applications. In particular, they have been recently suggested as promising nanoheaters. However, while the thermo-optical properties silicon germanium resonators to realize tunable metasurfaces based on external thermal inputs, effect self-induced optical heating onto their has so far neglected. this...

Zero reflection and complete light absorption are required in a wide range of applications ranging from sensing devices to solar heaters photoelectrodes. However, simultaneously satisfying the requirements broadband spectrum, omnidirectionality, polarization insensitivity, scalability is very challenging. Combining light-trapping characteristics microscale copper nanowires (Cu NWs) with unique optical properties carbon nanotubes (CNTs), we experimentally demonstrate novel perfect absorber...

Abstract Thermonanophotonics, that is the study of photothermal effects in optical nanoantennas, has recently attracted growing interest. In particular, going beyond thermoplasmonic designs, thermo‐optical modulation dielectric nanoantennas opens new opportunities for reconfigurable and non‐reciprocal metasurfaces. However, understanding light‐driven large arrays remains challenging. this work, first time impact single nanoresonator analyzed. By performing photo‐thermo‐optical computations...

Finite element simulations of the optical behavior gold nanostars in water reveal a new view collective electron cloud oscillations, where localized surface plasmon resonances coexist with coherent delocalized interface waves, i.e., propagating plasmons. Gold nanostar spikes long enough to allow polaritons and short resonate spherical core serve as substrate for observed overlap between modes hot spots. Transverse plane plots bulk coupled ones. In light these observations, we explore...

Gold nanostars display exceptional field enhancement properties and tunable resonant modes that can be leveraged to create effective imaging tags or phototherapeutic agents, design novel hot-electron based photocatalysts. From a fundamental standpoint, they represent important platforms study the dependence of hot carrier energy dynamics on plasmon band intensity position. Toward realization these platforms, holistic approaches taking into account both theory experiments behavior...

Finite element simulations through COMSOL Multiphysics were used to optically model systems composed of Mo dichalcogenide layers (MoTe2 and MoS2) Au nanoparticles (spherical dimers, nanorods, nanostars) understand how their fundamental material properties as well interactions affect the photocurrent response. The absorption cross sections various linearly increase with respect increasing dimensions, hence being ideal tunable for enhancement electric field in under visible near infrared....

Abstract Recent developments in the application of plasmonic nanoparticles have showcased importance understanding detail their resonances at single-particle level. These can be excited and probed through various methods, which grouped four categories, depending on whether excitation detection involve electrons (electron energy loss spectroscopy), photons (e.g., dark-field microscopy), or both (cathodoluminescence photon-induced near-field electron microscopy). While photon-based...

The near-infrared emissions of single-walled carbon nanotubes (SWCNTs) falls within the optical transparency window biological tissue, allowing deep-tissue, in vivo and vitro imaging. However, relatively low photoluminescence quantum yield SWCNTs, which typically lies range 0.1 - 1.5%, limits penetration depth sensitivity these fluorophores when used as imaging agents sensors. In present work, we enhance fluorescence emission SWCNTs up to 10-fold by employing different localized surface...

Luminescence constitutes a unique source of insight into hot carrier processes in metals, including those plasmonic nanostructures used for sensing and energy applications. However, being weak nature, metal luminescence remains poorly understood, its microscopic origin strongly debated, potential unravelling nanoscale dynamics largely unexploited. Here, we reveal quantum-mechanical effects emanating the from thin monocrystalline gold flakes. Specifically, present experimental evidence,...

Thanks to the compact design and multi-functional light-manipulation capabilities, reconfigurable metalenses, which consist of arrays sub-wavelength meta-atoms, offer unique opportunities for advanced optical systems, from microscopy augmented reality platforms. Although poorly explored in context metalens, thermo-optical effects resonant silicon nanoresonators have recently emerged as a viable strategy realize tunable meta-atoms. In this work, we report proof-of-concept an ultrathin (300 nm...

<div>Gold nanostars display exceptional field enhancement properties and tunable resonant modes that can be leveraged to create effective imaging tags or phototherapeutic agents, design novel hot-electron based photocatalysts. From a fundamental standpoint, they represent important platforms study the dependence of hot carrier energy dynamics on plasmon band intensity position. Toward realization these platforms, holistic approaches taking into account both theory experiments behavior...

Gold nanostars display exceptional field enhancement properties and tunable resonant modes that can be leveraged to create effective imaging tags or phototherapeutic agents, design novel hot-electron based photocatalysts. From a fundamental standpoint, they represent important platforms study the dependence of hot carrier energy dynamics on plasmon band intensity position. Toward realization these platforms, holistic approaches taking into account both theory experiments behavior...

Gold nanostars are well-known as effective substrates for applications in which near field enhancements sought, owing to their uniquely sharp protruding spikes. In particular, we have shown how they can be employed build sensing platforms the direct identification of small molecule analytes via surface enhanced Raman spectroscopy (SERS) achieving femtomolar limits detection. We also demonstrated conjugated peptides cancerous cells, and aptamers targeting recognition prostate cancer with...

Thermonanophotonics, i.e. the study of photothermal effects in optical nanoantennas, has recently attracted growing interest. While thermoplasmonic structures enable a broad range applications, from imaging and optofluidics devices to medical photochemical systems, dielectric nanoantennas open new opportunities for thermo-optical modulation reconfigurable metasurfaces. However, computing both photo-thermal large arrays remains challenge. In this work, we implement fast numerical method...

Active optical components are essential building blocks for a wide variety of applications such as communications, microscopy, and illumination systems. Reconfigurable metasurfaces, which consist arrays subwavelength meta-atoms, can be engineered to uniquely realize compact multifunctional elements, enabling light-polarization dynamic-control well beam steering, focusing or zooming. Varifocal metalenses, in particular, have attracted increasing interests. Yet, going beyond mechanical...