An oblique-angle infrared circular polarization filter using a Bezier surface representation

This paper proposes a method to determine CO2 concentration by measuring relative circular polarization using 2D periodic unit cells of Bezier surfaces optimized using the Covariance Matrix Adaptation Evolution Strategy. The CO2 absorption spectrum has a peak which can be useful for measurement at 4.3 μm. A filter was designed to separate circularly polarized components of light at this frequency using the Covariance Matrix Adaptation Evolutionary Strategy (CMA-ES). The filter presented is capable of blocking the effects due to nearby absorption bands such as the N2O band at 4.5 μm.