We report on the formation of one- and two-dimensional (1D and 2D) nanohole arrays on the surface of a silicon wafer by scanning with a femtosecond laser with appropriate power and speed. The underlying physical mechanism is revealed by numerical simulation based on the finite-difference time-domain technique. It is found that the length and depth of the initially formed gratings (or ripples) plays a crucial role in the generation of 1D or 2D nanohole arrays. The silicon surface decorated with such nanohole arrays can exhibit vivid structural colors through efficiently diffracting white light.
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http://dx.doi.org/10.1364/OL.37.001106 | DOI Listing |
In this study, we propose a double-layer elliptical nanohole array (DLEN) and investigate its chiral properties using the finite element method. The DLEN structure simultaneously exhibited asymmetric reflection (AR), circular dichroism (CD), and asymmetric transmission (AT) effects with specific measured values. By analyzing the full cycle of plasmon resonance modes, we identified that the local rotational resonance excited by circular polarized light (CPL) is important in the conversion of right circularly polarized (RCP) and left circularly polarized (LCP) light upon reflection and transmission.
View Article and Find Full Text PDFACS Omega
December 2024
Division of Solid-State Electronics, Department of Electrical Engineering, The Ångström Laboratory, Uppsala University, SE-751 03 Uppsala, Sweden.
Extracellular vesicles (EVs) are nanoparticles encapsulated with a lipid bilayer, and they constitute an excellent source of biomarkers for multiple diseases. However, the heterogeneity in their molecular compositions constitutes a major challenge for their recognition and profiling, thereby limiting their application as an effective biomarker. A single-EV analysis technique is crucial to both the discovery and the detection of EV subpopulations that carry disease-specific signatures.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
December 2024
Department of Chemical Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada.
Hybrid nanoplasmonic structures composed of subwavelength apertures in metallic films and nanoparticles have recently been demonstrated as ultrasensitive plasmonic sensors. This work investigates the electrokinetically driven propagation of the assembly mechanism of the metallic nanoparticles through nanoapertures. The Debye-Hückel approximation for a symmetric electrolyte solution with overlapping electrical double layers (EDLs) is used to obtain an analytical solution to the problem.
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November 2024
Advanced Laboratory of Electro-Optics (ALEO), Department of Applied Physics/Electro-Optics Engineering, Lev Academic Center, Jerusalem 9116001, Israel.
Plasmonic nanostructure arrays, designed for performance as pixels in an advanced SERS imaging device, were fabricated by gallium focused ion beam (FIB). Though the FIB is best suited for etching holes and negative structures, our previously reported simulations favor protrusions. Herein, we report on the FIB methodology to "sculpt" positive structures by "ion-blasting" away the surrounding material.
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