1,721,036 research outputs found
Smart micro-opto-fluidic sensing platforms for contactless chemical and biological analyses
Full text linkTowards the Development of a SWIR-LEDs Based Optoelectronic System for Urea Monitoring During Haemodialytic Therapy
No full textSpectral Interferometric Detection of NIR Optical Resonances of Rectangular Micro-Capillaries for Refractive Index Sensing
No full textA Smart Optofluidic Sensing Platform Ensuring Patients' Safety During Parenteral Nutrition Administration
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Interacting metal nanoparticles: Optical properties from nanoparticle dimers to core-satellite systems
No full textPrompted by the growing interest in the optical properties of coupled metal nanoclusters, we implemented a code in the framework of Generalized Multiparticle Mie theory (GMM) to simulate far-field properties of strongly interacting spherical particles. In order to validate the code different case studies, including systems modeled for the first time, have been treated. The extinction properties of noble metal nanocluster dimers, chains and core-satellite structures have been computed. Influence of parameters like interparticle distance, incident field polarization, number of multipolar expansions and chain length has been studied. The code provided reliable results in agreement with previous works and proved to be affordable and robust in any of the treated case
Local-field enhancement in metallic nanoplanets
No full textGeneralized Multiparticle Mie theory is applied in order to study in detail local-field properties of metallic nanoplanets (i.e., a central cluster surrounded by small "satellite" clusters very close to its surface), obtained by ion beam techniques. Strongly asymmetric dimers are chosen as model systems in order to establish the influence of topological parameters such as satellite dimension and distance from the central cluster surface on the local-field enhancement, with calculated enhancement factors as high as similar to 180 in the case of silver. Similar topological configurations are shown to be present in typical nanoplanet systems, with comparable local-field enhancement factors. Simulations for silver and silver-gold alloy in silica, and for gold in titania matrix are reported as examples of possible experimental systems
Femtosecond nonlinear absorption of gold nanoshells at surface plasmon resonance
No full textThe nonlinear optical absorption of gold nanoshells (Au NSs) of different size, in water, was investigated using open aperture z-scan technique with femtosecond laser pulses at 806 nm. It is found that, in general, NSs behave as saturable absorbers. The level of saturation depends on the Au NSs structure and precisely on the ratio between the core size and shell thickness. The measured values of the nonlinear absorption coefficient show a dependence on both the repetition rate and the pulse energy. An average value of the nonlinear absorption coefficient beta = -4.5 +/- 1.0 x 10(-11) cm W(-1) is obtained from z-scan data of core-shell particles of inner and outer radius 95 and 110 nm, respectively, measured at 20 Hz repetition rate in the energy range 120-300 nJ
Local-field enhancement and plasmon tuning in bimetallic nanoplanets
Full text linkA full-interaction electromagnetic approach is applied to interpret the local-and far-field properties of AuAg alloy nanoplanets (i.e. a central cluster surrounded by small "satellite" clusters very close to its surface) fabricated in silica by ion implantation and ion irradiation techniques. Optical extinction spectroscopy reveals a large plasmon redshift which is dependent on the irradiation conditions. Simulations strongly suggest that the peculiar topological arrangement of the satellite clusters is responsible for the observed plasmonic features. Theoretical results also indicate that strong local-field enhancement is obtained between coupled clusters. Calculations for Ag models show that enhancement factors as high as similar to 100 are readily achievable
A Dual-Region Fiber-Optic SPR Biosensor with Self-Referencing Compensation of Bulk Refractive Index and Temperature Effects
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