Year: 2019
Type: article
Abstract: The design of achromatic optical components requires materials with high transparency and low dispersion. We show that although metals are highly opaque, densely packed arrays of metallic nanoparticles can be more transparent to infrared radiation than dielectrics such as germanium, even when the arrays are over 75% metal by volume. Such arrays form effective dielectrics that are virtually dispersion-free over ultra-broadband ranges of wavelengths from microns up to millimeters or more. Furthermore, the local refractive indices may be tuned by altering the size, shape, and spacing of the nanoparticles, allowing the design of gradient-index lenses that guide and focus light on the microscale. The electric field is also strongly concentrated in the gaps between the metallic nanoparticles, and the simultaneous focusing and squeezing of the electric field produces strong 'doubly-enhanced' hotspots which could boost measurements made using infrared spectroscopy and other non-linear processes over a broad range of frequencies.
Source: Nature Communications
Institutions: Imperial College London, Universitat Rovira i Virgili, Centro de Investigación Biomédica en Red de Salud Mental, Universidade de Vigo, Ludwig-Maximilians-Universität München, Institució Catalana de Recerca i Estudis Avançats, Consejo Superior de Investigaciones Científicas, Instituto de Estructura de la Materia
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $5,200
Funders: Banco Santander, Solar Technologies go Hybrid, Leverhulme Trust, Imperial College London, European Commission, Deutsche Forschungsgemeinschaft, Xunta de Galicia, U.S. Air Force, Engineering and Physical Sciences Research Council, European Regional Development Fund, Air Force Office of Scientific Research, European Office of Aerospace Research and Development
Awards: G1072749480, Mathematical fundamentals of Metamaterials for multiscale Physics and Mechanics, G1523888516, G260750634, EPSRC Centre for Doctoral Training in Theory and Simulation of Materials, G2763365579, G4041055337, G4065017476, G632910720, G6438965579, G6731907685, G7090116110, G7742714466, G8351451957, G8552877082
OpenAlex ID: W2963782690