FDTD simulation on transmittance of silica microsphere thin films with varying embedding in an optical adhesive

Abstract

Moth-eye inspired nanostructure is widely used in optical applications. In this numerical study, a new type of anti-reflection film is designed using finite difference time domain method (FDTD). A three-dimensional model is established, simulating a monolayer of close-packed silica nanoparticle film embedded in a layer of polymeric optical adhesive. FDTD simulation is carried out in the visible band of wavelength, in order to investigate the transmittance of light propagation through the silica nanoparticle and adhesive layer. The effect of size of nanostructure as well as the embedding degree of optical adhesive are compared on different substrates, including visible transparent substrates with lower refractive index, i.e., fused silica glass, PMMA, PS, and visible opaque silicon substrate, with high refractive index. The numerical results reveal that we can obtain the best optical performance with nanoparticle size of 200 nm in diameter, while the immersion degree has different effects on different substrates.