Infrared Plasmonics with Indium–Tin-Oxide Nanorod Arrays

This article reports the study of infrared plasmonics with both random and periodic arrays of indium–tin-oxide (ITO) nanorods (NR). A description is given on the synthesis, patterning, and characterization of physical properties of the ITO NR arrays. A classical scattering model, along with a 3-D finite-element-method and a 3-D finite-difference-time-domain numerical simulation method has been used to interpret the unique light scattering phenomena. It is also shown that the intrinsic plasma frequency can be varied through careful postsynthesis processing of the ITO NRs. Examples are given on how coupled plasmon resonances can be tuned through patterning of the ITO NR arrays. In addition, environment dielectric sensing has been demonstrated through the shift of the resonances as a result of index change surrounding the NRs. These initial results suggest potential for further improvement and opportunities to develop a good understanding of infrared plasmonics using ITO and other transparent conducting oxide semiconducting materials.