Achievement

RPI IGERT trainee Tim Walsh (EE) supervised by IGERT faculty Shawn Lin (Physics) achieved an efficient THz radiation through thermal excitation. This has not been possible before because of the constraint of thermal-dynamic Wien's law that predicts a much higher frequency radiation of 30-300 THz at elevated temperatures of T>300-1000 K. The innovation is to use a 3D metallic tungsten (W) photonic crystal nanostructure with a conformal, atomic-layer deposition of Iridium metal coating to modify the optical properties of the structure and overcome this fundamental challenge. With a thin Ir coating the band edge of a pinned W lattice is pushed from 1.6 um to below 1 um. This coating facilitates the formation of a large photonic band gap in the infrared and near-infrared wavelength. The bandgap can then be utilized to inhibit those thermal radiation predicted by the Wien's law and, at the same time, enhances those radiations in the THz regime. The work was published in Optical Physics.