Refractive-index matched polymer to water

We report a polymer refractive index-matched with water at room temperature and that can be cast in thick specimens.  We cast it to thicknesses up to 3 mm and by using appropriate primer glued it to fused silica and acrylic viewports.  Specifics of the mold fabrication and casting process will be presented. We successfully demonstrated its use with three common laser-based diagnostics: laser-induced fluorescence (LIF), particle image velocimetry (PIV), and molecular tagging velocimetry (MTV).