CONICET | Buscador de Institutos y Recursos Humanos

A new platform for optical sensing will be presented, based on the resonant excitation of Tamm surface plasmons [1]. These electromagnetic modes, confined at the interface between a noble metal layer and a one-dimensional photonic crystal (Distributed Bragg Reflector, DBR), offer a promising alternative to conventional surface plasmon resonance sensors, combining high sensitivity and facile instrumentation [2]. Mesoporous multilayers of SiO2 and TiO2 terminated with a 30 nm gold film were characterised by UV-vis transmission spectroscopy at normal incidence, revealing a peak associated with the excitation of Tamm plasmons within the photonic stop band. The structure was exposed to a range of organic solvents, and the spectral position of the resonance monitored to demonstrate its sensitivity to local variations of refractive index. We will discuss the instrumental role of permeable multilayers in the design of this structure, allowing the analyte to access regions of high electric field near the metal surface. The mesoporous oxide layers further complement this device with unique features, such as selective chemical functionalisation enabling specific recognition, nano-filtering, large surface-to-volume ratio, and mechanical strength. Numerical simulations will be presented that fully support the experimental observations. Furthermore, theoretical conditions for critical coupling between light and Tamm plasmons will be discussed, providing guidelines for optimised Tamm structures. References [1] M. Kaliteevski, I. Iorsh, S. Brand, R. Abram, J. Chamberlain, A. Kavokin, and I. Shelykh. Phys. Rev. B, 76(16):165415, (2007). [2] B. Auguié, M. C. Fuertes, P. C. Angelomé, N. L. Abdala, G. J. A. A. Soler Illia, and A. Fainstein. ACS Photonics, 1(9):775?780 (2014).

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