Switchable optics based on guided mode resonance in lithographically patterned vanadium dioxide

Vanadium dioxide as a phase change material is usually known for its consideration in smart window applications. However, the attention shifts to using it in actively switched optical elements. The main challenges are the deposition of vanadium dioxide with the correct stoichiometry and phase and the patterning of the material. We propose a design with a corresponding manufacturing process for an actively switchable reflector at 1550 nm wavelength with a contrast near 105 by using the thermochromic effect of vanadium dioxide. The reflectance of the proposed optical element can be controlled between an ultra-low and a high reflecting state. We elaborate on the proposed optical design, the manufacturing process including deposition, annealing and patterning processes, and discuss already achieved results.