Mid-infrared (mid-IR) detection and imaging over atmospheric transparent 3-5 μm and 8-12 μm bands are increasingly becoming important for various space, defense and civilian applications. Various kinds of microbolometers offer uncooled detection of IR radiation. However, broadband absorption of microbolometers makes them less sensitive to spectrally resolved detection of infrared radiation and the fabrication is also very tedious involving multiple complex lithography steps. In this study, we designed an optical nano-antenna array based detector with narrow frequency band of operation. The structure consists of a two-element antenna array comprised of a perforated metallic hole array coupled with an underneath disk array which trap incident radiation as dipole currents. The energy is dissipated as electron plasma loss on the hole-disk system inducing close to ~100% absorption of the incident radiation. This near perfect absorption originates from simultaneous zero crossing of real component of permittivity and permeability due to the geometrical arrangement of the two antenna elements which nullifies overall charge and current distributions, prohibiting existence of any propagating electromagnetic modes at resonance. Moreover, the continuous perforated film allows probing of the induced "micro-current" plasma loss on each nano hole-disk pair via a weak bias current. Such optical antenna design enables flexible scaling of detector response over the entire mid-infrared regime by change in the antenna dimensions. Furthermore, the development of simple nanoimprint lithography based large area optical antenna array fabrication technique facilitates formation of low cost frequency selective infrared detectors.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd-2235 |
| Date | 01 January 2014 |
| Creators | Modak, Sushrut |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations |
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