Efficient reflectance modulation by multilayers containing a phase change material

Abstract

Applications of vanadium dioxide (VO2) in photonics operate mostly in transmission since absorbance is highly modulated during the phase transition. Whereas transmittance may switch by orders of magnitudes through sub-wavelength films, effects in reflection are typically much weaker. Here we investigate a multilayer structure with VO2 that allows for efficient reflectance switching over the 1000 to 2000 nm spectral region, with reflectance changing by more than a factor of 50 at some wavelengths. Low-reflectance states reach values <1%, with the system acting as a nearly perfect absorber. The structure has the advantage of involving only materials that are compatible with the harsh fabrication conditions of VO2, namely SiO2 and gold. We present simulation results that can be used to select optimal material configuration and carry out experimental demonstrations of the concept.