Narrow-band and polarization cut-offfiltering based on the bionic structure of unidirectional microvilli array

Based on assumption of the visual system characteristics of the unidirectional microvilli array, this paper simulated the bionic model. The unidirectional microvilli array is simulated and it is simplified as cylinders, which is composed of material with index of refraction of n2 periodically arranged and is surrounded by medium with index of refraction of n1. Then, the bionic structure is equivalent to numbers of binary grating layers with different periods and thicknesses. Based on the effective medium theory (EMT) and transfer matrix method, this paper analyzed the relation between the transmittance of s-and p-modes and wavelengths in visible spectrum (400nm-700nm) for this bionic model. The result shows that the bionic model can work as a polarizer in two different narrow spectral ranges, and in two orthogonal polarization direction and can achieve the function of narrow-band and polarization cut-off filtering. Changing the thicknesses of the binary grating layers, the spectrum band of two spectral ranges would be different.