'Plasphonics' could lead to improved far-IR sensors

March 5, 2013
Scientists in France and Singapore have both analytically and numerically modeled types of hybrid electromagnetic modes that they call plasphonic modes.

Scientists at CNRS Centre d’Elaboration des Materiaux et d’Etudes Structurales and the Université de Toulouse (both in Toulouse, France) and the Agency for Science, Technology, and Research (Research Link, Singapore) have both analytically and numerically modeled types of hybrid electromagnetic modes that they call plasphonic modes. The results could lead to a new area of research that the researchers dub “plasphonics.” The phenomenon occurs when localized surface plasmons in a metallic nanoantenna interact with delocalized phonons at the surface of a heteropolar semiconductor.

Using a so-called “Green dyadic numerical simulation,” the group found that when the frequency of surface plasmons matched those of surface phonons, the result was a strong local field enhancement. In the model, a gold (Au) antenna was placed a height Z away from a gallium nitride (GaN) semiconducting surface, illuminated by an incident electric field (E0). The electric field was enhanced by up to a factor of 10 through the plasphonic effect. Then, the researchers introduced the concept of an active surface in which the electromagnetic field carried by the phonons is harvested by the antenna, leading to an even greater field enhancement. The interaction enables optical resonances to be fine-tuned, potentially enabling far-infrared (far-IR) photonic devices and sensors based on plasphonics. Contact Adnen Mlayah at [email protected].

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

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