Organic Anisotropic Excitonic Optical Nanoantennas. Issue 23 (26th May 2022)

• Record Type: Journal Article
• Authors: Kang, Evan S. H.; KK, Sriram; Jeon, Inho; Kim, Jehan; Chen, Shangzhi; Kim, Kyoung‐Ho; Kim, Ka‐Hyun; Lee, Hyun Seok; Westerlund, Fredrik; Jonsson, Magnus P.
• Is Part Of: Advanced science. Volume 9:Issue 23(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-26
• Subjects: hyperbolic polaritons -- J‐aggregates -- localized surface exciton resonances -- Mie resonances -- nanoantennas; Science -- Periodicals; 505
• DOI: 10.1002/advs.202201907
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: Optical nanoantennas provide control of light at the nanoscale, which makes them important for diverse areas ranging from photocatalysis and flat metaoptics to sensors and biomolecular tweezing. They have traditionally been limited to metallic and dielectric nanostructures that sustain plasmonic and Mie resonances, respectively. More recently, nanostructures of organic J‐aggregate excitonic materials have been proposed capable of also supporting nanooptical resonances, although their advance has been hampered from difficulty in nanostructuring. Here, the authors present the realization of organic J‐aggregate excitonic nanostructures, using nanocylinder arrays as model system. Extinction spectra show that they can sustain both plasmon‐like resonances and dielectric resonances, owing to the material providing negative and large positive permittivity regions at the different sides of its exciton resonance. Furthermore, it is found that the material is highly anisotropic, leading to hyperbolic and elliptic permittivity regions. Nearfield analysis using optical simulation reveals that the nanostructures therefore support hyperbolic localized surface exciton resonances and elliptic Mie resonances, neither of which has been previously demonstrated for this type of material. The anisotropic nanostructures form a new type of optical nanoantennas, which combined with the presented fabrication process opens up for applications such as fully organic excitonic metasurfaces. Abstract : Optical nanoantennas based on organic anisotropic J‐aggregate materials with strong exciton absorption provide dual functionality in the same nanostructure. They can support hyperbolic localized surface‐exciton polariton resonances on one spectral side of the exciton resonance while they support elliptic Mie resonances on the other side.