Plasmonic Color-Graded Nanosystems with Achromatic Subwavelength Architectures for Light Filtering and Advanced SERS Detection

Abstract

Plasmonic colour-graded systems are devices featuring a spatially variable plasmonic response over their surface. They are widely used as nanoscale colour filters; their typical size is small enough to allow integration with miniaturized electronic circuits paving the way to realize novel nanophotonic devices. Currently, most plasmonic colour-graded systems are intrinsically discrete, as their chromatic response exploits the tailored plasmon resonance of micro-architectures characterized by different size and/or geometry for each target colour.Here we report the realization of multifunctional plasmon-graded devices where continuouslygraded chromatic response is achieved by smoothly tuning the composition of the resonator material while simultaneously maintaining an achromatic nanoscale geometry. The result is a new class of versatile materials: we show their application as plasmonic filters with a potential pixel size smaller than half of the exciting wavelength, but also as multiplexed surface-enhanced Raman spectroscopy (SERS) substrates. Many more implementations, like photovoltaic efficiency boosters or colour routers await, and will benefit from the low fabrication cost and intrinsic plasmonic flexibility of the presented systems.

Thermometric Calibration of the Ultrafast Relaxation Dynamics in Plasmonic Au Nanoparticles

“…The samples consisted of 2D arrays of Au NPs fabricated by solid-state dewetting of ultrathin Au films onto a nanopatterned LiF(110) single crystal. The sample fabrication procedures are described in detail in previous works. ,− The system is composed of densely packed Au NPs (areal density 800 ± 100 NP/μm 2 ), with mean size around 20–25 nm, circular in-plane cross section, and short-range order, laid on a transparent LiF(110) substrate (Crystec Gmbh). An atomic-force microscopy image of the system is reported in the Supporting Information (Figure S1).…”

Antimicrobial Nanostructured Coatings: A Gas Phase Deposition and Magnetron Sputtering Perspective

“…Nanostructured materials (NMs) [1][2][3][4][5] represent an active area of research and a techno-economic sector in continuous expansion in many application domains, as shown by the more than 1400 review papers describing NMs applications that have appeared in the last three years. The technological importance of NMs is due to their tunable physicochemical characteristics, such as optical absorption [6][7][8], electrical conductivity [9,10], photothermal characteristics [11], optical [12,13] and photoacoustic sensing [14,15], surface enhanced Raman scattering effects [16,17], chemical state [18], and bactericidal functionalities [19][20][21]. In particular, the latter research sector has been driven by the interest in understanding the interactions and effects of nanoparticles (NPs) on living organisms [20][21][22][23][24][25][26][27], with prominent attention towards the wet synthesis of NMs and NPs and the study of their effect on cells and bacteria in solution.…”

Band Structure Engineering by Alloying for Photonics

“…The subsequent electromagnetic field propagates along the metal–dielectric interface with a much smaller wavelength than the incident light . These characteristics give rise to a strong electric field confinement near the surface, which allows for the manipulation of light at deep sub‐wavelengths, leading to a variety of applications including nanolasers, sensors, bioimaging, surface‐enhanced Raman spectroscopy, color displays, and others …”