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