Polarization beam splitter with disparate functionality in transmission and reflection modes

Achieving multiple diversified functionalities in a single flat device is crucial and practical for integration. Here we demonstrate a planar polarization beam splitter (PBS) capable of efficiently reflecting the x-linearly polarized (XLP) light while transmitting the orthogonal one. Other than separating the two orthogonal linearly polarized lights, a general design scheme is proposed, with which one can achieve disparate wavefront steering in transmission and reflection modes. For y-linearly polarized (YLP) incident lights, wavefront steering such as beam deflecting, beam focusing and vortex beam generating are exhibited in transmission mode. Switching the incident lights to XLP one, the metasurfaces exhibit disparate functionality, operating in reflection mode with the incident lights back reflected. With the merit of high efficient and polarization-dependent disparate functionality, the designed PBS can motivate the realizations of high-performance bifunctional metadevices and hold potential applications in optoelectronic and photonic circuits.