Infrared frequency-tunable coherent thermal sources

Infrared frequency-tunable coherent thermal sources Hao Wang, Yue Yang, and Liping Wang School for Engineering of Matter, Transport & Energy, Arizona State University, Tempe, Arizona, 85287, USA * Equal contribution. † Corresponding author. Email: [email protected], Phone: 1-404-727-8615 Submitted on October 24, 2014; Revised on January 18, 2015 Abstract In this work, we numerically demonstrate an infrared frequency-tunable selective thermal emitter made of graphene-covered silicon carbide (SiC) gratings. Rigorous coupled-wave analysis shows temporallycoherent emission peaks associated with magnetic polariton, whose resonance frequency can be dynamically tuned within the phonon absorption band of SiC by varying graphene chemical potential. An analytical inductor-capacitor circuit model is introduced to quantitatively predict the resonance frequency and further elucidate the mechanism for the tunable emission peak. The effects of grating geometric parameters, such as grating height, groove width and grating period, on the selective emission peak are explored. The direction-independent behavior of magnetic polariton and associated coherent emission are also demonstrated. Moreover, by depositing 4 layers of graphene sheets onto the SiC gratings, a large tunability of 8.5% in peak frequency can be obtained to yield the coherent emission covering a broad frequency range from 820 cm to 890 cm. The novel tunable metamaterial could pave the way to a new class of tunable thermal sources in the infrared region.