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 exciting magnetic resonance with phase transition of vanadium dioxide (VO2). Numerical simulation shows a broad absorption peak at the wavelength of 10.9 um when VO2 is a metal, but it shifts to 15.1 um when VO2 changes to dielectric phase below its phase transition temperature of 68degC. The large tunability of 38.5% in the resonance wavelength stems from the different excitation conditions of magnetic resonance assisted 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 plasmon-phonon coupling is also discussed. The results here would be beneficial for active control in novel electronic, optical and thermal devices. 
Hao Wang, Yue Yang, Liping Wang
physics.optics