UCLA

In this study, cubic and hexagonal mesoporous amorphous silica thin �lms were synthesized using evaporation-induced self-assembly process followed by calcination leaving highly ordered spherical or cylindrical pores in a silica matrix. The �films featured pores with diameter between 4 and 11 nm, lattice parameter from 7.8 to 24 nm, and porosity between 22% and 45%. All �films were dehydrated prior to reflectance measurements except for one �film which was fully hydrated. The present study compares the spectral reflectance measured experimentally between 400 and 900 nm with that computed numerically by solving three-dimensional Maxwell's equations in mesoporous silica thin �films with the same morphology as those synthesized. The matrix was assumed to have the same optical properties as bulk fused silica. The pore optical properties were either those of air or liquid water whether the fi�lm was dehydrated or hydrated, respectively. Excellent agreement was found between experimental and numerical reflectance for both cubic and hexagonal mesoporous silica �films. This study experimentally validates our simulation tool and o�ffers the prospect of ab-initio design of nanocomposite materials with arbitrary optical properties without using e�ffective medium approximation or mixing rules.