Wavelength-tunable infrared metamaterial by tailoring magnetic resonance condition with VO2 phase transition

In this work, we report the design of a wavelength-tunable infrared metamaterial by tailoring magnetic resonance condition with the phase transition of vanadium dioxide (VO2). Numerical simulation based on the finite-difference time-domain method shows a broad absorption peak at the wavelength of 10.9 mu m when VO2 is a metal, but it shifts to 15.1 mu m when VO2 changes to dielectric phase below its phase transition temperature of 68 degrees C. The large tunability of 38.5% in the resonance wavelength stems from the different excitation conditions of magnetic resonance mediated by plasmon in metallic VO2 but optical phonons in dielectric VO2. The physical mechanism is elucidated with the aid of electromagnetic field distribution at the resonance wavelengths. A hybrid magnetic resonance mode due to the plasmon-phonon coupling is also discussed. The results here would be beneficial for active control of thermal radiation in novel electronic, optical, and thermal devices. (C) 2014 AIP Publishing LLC.