Simultaneous balancing of geometric transformation and linear polarizations using six-fold-mirror geometry over the visible region

The presence of optical rotation due to the Berry phase and coating-induced linear polarizations across a set of rays deteriorate the form of a point spread function. In this Letter, we model an optical system with six aluminum coated fold mirrors, and we show how to balance geometric transformation, linear retardance, and linear diattenuation simultaneously. We minimize the linear polarizations by arranging the six fold mirrors in three pairs of crossedfold- mirror geometry. In the same optical model, we also show that geometric transformation induced by the first set of three mirrors is canceled out by the second set of three mirrors by rotating the eigen-polarizations in opposite direction with the same amount. We perform experimental verification using a spectroscopic Mueller matrix polarimeter over the visible spectral range.