Enhanced UV upconversion emission using plasmonic nanocavities

• Published in: Optics express Vol. 24; no. 13; pp. 13999 - 14009
• Main Authors: El Halawany, Ahmed, He, Sha, Hodaei, Hossein, Bakry, Ahmed, Razvi, Mir A N, Alshahrie, Ahmed, Johnson, Noah J J, Christodoulides, Demetrios N, Almutairi, Adah, Khajavikhan, Mercedeh
• Format: Journal Article
• Language: English
• Published: United States Optical Society of America 27.06.2016
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.24.013999

Upconversion of near infrared (NIR) into ultraviolet (UV) radiation could lead to a number of applications in bio-imaging, diagnostics and drug delivery. However, for bare nanoparticles, the conversion efficiency is extremely low. In this work, we experimentally demonstrate strongly enhanced upconversion emission from an ensemble of β-NaYF :Gd /Yb /Tm @NaLuF core-shell nanoparticles trapped in judiciously designed plasmonic nanocavities. In doing so, different metal platforms and nanostructures are systematically investigated. Our results indicate that using a cross-shape silver nanocavity, a record high enhancement of 170-fold can be obtained in the UV band centered at a wavelength of 345 nm. The observed upconversion efficiency improvement may be attributed to the increased absorption at NIR, the tailored photonic local density of states, and the light out-coupling characteristics of the cavity.