Transmission increase upon switching of v O2 thin films on microstructured surfaces

The authors compare transmission measurements of near-infrared light through V O2 thin films on smooth substrates and on ordered arrays of silica microspheres. When the samples are heated above the critical temperature for the semiconductor-metallic phase transition, smooth thin films show reduced transmission independent of thickness; however, the V O2 film deposited on the microspheres may show either reduced or enhanced transmission, depending on V O2 film thickness. They show that this at a first glance, unexpected behavior is directly related to the change of scattering efficiency upon the phase transition. This suggests that optical transmission through thin-film microstructures could be tuned by an appropriate combination of microsphere ordering and V O2 film thickness