Super-broadband geometric phase devices based on circular polarization converter with mirror symmetry

We propose a simple implementation to obtain super-broadband geometric phase devices (GPD) by means of circular polarization converter (CPC) with mirror symmetry. demonstrate that the best choice wideband GPDs and CPCs is symmetric structure. Based on two-rotation model Poincaré sphere, optimization parameters time are significantly reduced. The CPC can be extended GPD, such as gratings (PGs), using holography. simulate diffraction efficiencies PGs. In normal incident case, efficiency over 99% in 420–945 nm, oblique first-order 90% range ±30°. show potential advantages wide color display spectral imaging.