Light absorber based on nano-spheres on a substrate reflector
2013 (English)In: Optics Express, ISSN 1094-4087, Vol. 21, no 6, 6697-6706 p.Article in journal (Refereed) Published
We systematically study a type of plasmonic light absorber based on a monolayer of gold nano-spheres with less than 30 nm in diameters deposited on top of a continuous gold substrate. The influences of particle size, inter-particle distance, particle-substrate spacer size etc on the resonance are studied thoroughly with a 3D finite-element method. We identified that the high-absorption resonance is mainly due to gap plasmon (coupled through particle bodies) when the separation between neighboring nano-spheres is small enough, such as close to 1 nm; at larger particle separations, the resonance is dominated by particle dipoles (coupled through the host dielectric). Experimentally, an absorber was fabricated based on chemically-synthesized gold nanoparticles coated with silica shell. The absorber shows a characteristic absorption band around 810 nm with a maximum absorbance of approximately 90%, which agrees reasonably well with our numerical calculation. The fabrication technique can be easily adapted for devising efficient light absorbers of large areas.
Place, publisher, year, edition, pages
2013. Vol. 21, no 6, 6697-6706 p.
Plasmonic Nanostructures, Perfect Absorber, Nanoparticles, Metamaterials, Enhancement, Devices
Other Physics Topics
IdentifiersURN: urn:nbn:se:kth:diva-122118DOI: 10.1364/OE.21.006697ISI: 000316796000006ScopusID: 2-s2.0-84875754313OAI: oai:DiVA.org:kth-122118DiVA: diva2:621257
FunderSwedish Research Council
QC 201305142013-05-142013-05-132013-11-04Bibliographically approved