A Study on the Suitability of Indium Nitride for THz Plasmonics

A. Shetty[1], K. J. Vinoy[1], S. B. Krupanidhi[2]
[1]Electrical Communication Engineering, Indian Institute of Science, Bangalore, India
[2]Materials Research Centre, Indian Institute of Science, Bangalore, India

As interest in the electromagnetic spectrum expands towards the infrared and terahertz range, the distinct advantages of using semiconductors instead of metals for plasmonic applications must be understood. Plasmonic resonances in gold (Au) and indium nitride (InN) gratings are studied, in the terahertz (?=30┬Ám) regime. The electromagnetic properties of Au and InN are described by the Drude model. InN, has a lower plasma resonance frequency of fp ? 52 x 1012 Hz (Far IR) as compared to that of Au which has fp ? 2.18 x 1015 Hz (optical range). This leads to InN plasmonic structures demonstrating a greater confinement of surface waves to the interface and greater field enhancement (~1.4 times) as compared to Au in the THz regime.