Experimental measurement of plasmonic nanostructures embedded in silicon waveguide gaps

“© 2016 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited"In this work, we report numerical simulations and experiments of the optical response of a gold nanostrip embedded in a silicon strip waveguide gap at telecom wavelengths. We show that the spectral features observed in transmission and reflection when the metallic nanostructure is inserted in the gap are extremely different than those observed in free-space excitation. First, we find that interference between the guided field and the electric dipolar resonance of the metallic nanostructure results in highcontrast (> 10) spectral features showing an asymmetric Fano spectral profile. Secondly, we reveal a crossing in the transmission and reflection responses close to the nanostructure resonance wavelength as a key feature of our system. This approach, which can be realized using standard semiconductor nanofabrication tools, could lead to a full exploitation of the extreme properties of subwavelength metallic nanostructures in an on-chip configuration, with special relevance in fields such as biosensing or optical switching.We acknowledge support from the Spanish Ministry of Economy and Competiveness (MINECO) under grants TEC2014-51902-C2-1-R and TEC2014-61906-EXP, and the Valencian Conselleria d'Educacion, Cultura i Esport under grant PROMETEOII/2014/034.Espinosa-Soria, A.; Griol Barres, A.; Martínez Abietar, AJ. (2016). Experimental measurement of plasmonic nanostructures embedded in silicon waveguide gaps. Optics Express. 24(9):9592-9601. doi:10.1364/OE.24.009592S9592960124