A metasurface-based direct-reading linear polarization analyzer

Abstract

Polarization state is one of the fundamental properties of electromagnetic (EM) wave, which has been widely investigated in fields of information encryption, remote sensing and multifunctional devices etc The existing methods for polarization detection are generally based on the measurement of Stokes parameters or the amplitude and phase difference between orthogonal components or polarization-dependent imaging. However, they generally requires post-possessing process to identify the polarization state or suffer from the shortcomings of limited detection states, which results in less intuitiveness and limited practical values of those methods. Here, we proposed a metasurface-based and direct-reading linear polarization analyzer, which could reveal the polarization angle of linearly incident plane wave in imaging way by utilizing geometric phase effect. Different linear polarization angles lead to the different positions of the brightest spot, and the polarization state of incident wave could be directly read out by comparing the position of the brightest spot and the index of reference spots above. Besides, this method could be generalized to simplify the process of detecting arbitrary polarization states, with which only the intensity ratio between orthogonal circularly polarized components needs to be measured. Moreover, a digital linear polarization analyzer is designed based on the similar method, which helps to reveal the linear polarization angle digitally and is much more straightforward for linear polarization detection. The proposed direct-reading linear polarization analyzer has the potential of being applied in fields of smart sensing and the development of human-computer interaction system etc.