Optical scattering during phase transition of vanadium dioxide

It is generally assumed that changes in optical properties of vanadium dioxide, such as transmittance and reflectance, during phase transition originate from modified refractive indices and interference effects. In this study, we show that up to 50% of losses during phase transition is in fact created by enhanced optical scattering. From simultaneous measurements of diffuse and specular transmission and reflection, a detailed account of scattering losses is obtained. Since optical scattering only increases in the temperature range corresponding to the phase transition, it suggests the growth of metallic islands from nucleation sites may be the underlining scattering mechanism. Optical scattering offers an alternative method to study this important material and could have consequences for some applications such as optical switches and waveguides.