Numerical analysis of an infrared gas sensor utilizing an indium-tin-oxide-based plasmonic slot waveguide
<p>Plasmonic waveguides have attracted much attention owing to the associated high field intensity at the metal–dielectric interface and their ability to confine the modes at the nanometer scale. At the same time, they suffer from relatively high propagation loss, which is due to the presence...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-01-01
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| Series: | Journal of Sensors and Sensor Systems |
| Online Access: | https://jsss.copernicus.org/articles/11/15/2022/jsss-11-15-2022.pdf |
| Summary: | <p>Plasmonic waveguides have attracted much attention owing
to the associated high field intensity at the metal–dielectric interface and
their ability to confine the modes at the nanometer scale. At the same time,
they suffer from relatively high propagation loss, which is due to the
presence of metal. Several alternative materials have been introduced to
replace noble metals, such as transparent conductive oxides (TCOs). A
particularly popular TCO is indium tin oxide (ITO), which is compatible with
standard microelectromechanical systems (MEMS) technology. In this work, the feasibility of ITO as an
alternative plasmonic material is investigated for infrared absorption sensing
applications: we numerically design and optimize an ITO-based
plasmonic slot waveguide for a wavelength of 4.26 <span class="inline-formula">µ</span>m, which is the absorption
line of CO<span class="inline-formula"><sub>2</sub></span>. Our optimization is based on a figure of merit (FOM), which
is defined as the confinement factor divided by the imaginary part of the effective mode
index (i.e., the intrinsic damping of the mode). The obtained optimal FOM is
3.2, which corresponds to 9 <span class="inline-formula">µ</span>m and 49 % for the propagation length
(characterizing the intrinsic damping) and the confinement factor,
respectively.</p> |
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| ISSN: | 2194-8771 2194-878X |