24 February 2017 Infrared photonic to plasmonic couplers using spray deposited conductive metal oxides
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Proceedings Volume 10105, Oxide-based Materials and Devices VIII; 101050E (2017) https://doi.org/10.1117/12.2254315
Event: SPIE OPTO, 2017, San Francisco, California, United States
In recent years, infrared plasmonics has turned towards materials that are wavelength and application tailorable, and which are geared towards CMOS processing. The transparent conductive oxides are very favorable towards infrared plasmonic applications for a number of reasons, one of which being the natural visible transparency due to their relatively large bandgap. Fluorine-doped tin oxide (FTO) is one such transparent and doping-tunable material that in addition is low cost due to spray deposition techniques that result in perfectly conformal coatings. In this work, a deposition recipe that gives high free carrier concentration was used to fabricate structures for demonstration of surface plasmon excitation. 1D gratings with a range of structural parameters were etched in silicon. Then the gratings were conformally coated with FTO by aqueous spray deposition. Excitation of surface plasmon polaritons (SPP) at mid- and long- wave infrared wavelengths on these gratings was demonstrated. The observed (SPP) excitation resonances agree will with analytical excitation calculations and numerical simulations. We show that grating heights of ~10-15% of the wavelength are optimum for achieving the strongest sharpest coupling to plasmonic resonances in the mid- and longwave infrared. The presented results are compared with similar etched silicon gratings coated with Ga-doped ZnO (GZO). The dominant difference between our FTO and GZO measurements is the free carrier concentration. The useful wavelength range is predicted for FTO based plasmonics and compared with other plasmonic host materials. The work presented here could play a key role in novel decreased-cost detectors, filters, and on-chip optoelectronics.
© (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Justin W. Cleary, Justin W. Cleary, Ricky Gibson, Ricky Gibson, Evan M. Smith, Evan M. Smith, Shiva Vangala, Shiva Vangala, Isaiah O. Oladeji, Isaiah O. Oladeji, Farnood Khalilzadeh-Rezaie, Farnood Khalilzadeh-Rezaie, Kevin Leedy, Kevin Leedy, Robert E. Peale, Robert E. Peale, } "Infrared photonic to plasmonic couplers using spray deposited conductive metal oxides", Proc. SPIE 10105, Oxide-based Materials and Devices VIII, 101050E (24 February 2017); doi: 10.1117/12.2254315; https://doi.org/10.1117/12.2254315

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