Energy flow difference structure design based on micro hemisphere structure

Currently, unidirectional energy flow films mainly rely on surface plasma polarization and photonic crystals, their working bands are narrow and they are mainly used in the field of optical communication. This paper simulates and optimizes an optical array film attached with a large number of micro hemispheres. When the parallel incident light is incident from the inner side of the film (A side) to the outer side (B side), most of the incident light can pass through the film to the outer side at different angles; when the parallel incident light is incident from the outer side to the inner side, a considerable portion of the incident light returns to the outer side when the incident angles are larger than 60°. Therefore, the film will generate energy flow difference. Although the energy flow difference cannot reach 100%, the working band of the film is relatively broad. In this paper, the height and refractive index of the micro hemisphere are continuously optimized, and the maximum energy flow difference reaches up to 97.5% at the angle of 80° eventually.