Generation of the Bessel Beam of Longitudinally Varied Polarization with Dielectric Metasurfaces

The beam with longitudinally varied polarization provides a new dimension for polarization applications, such as material processing, longitudinal depth detection, optical communications, etc. A few different methods have so far been investigated, including spatial light modulators and diffractive optical elements. However, these methods have complex optical path, large volume, which are difficult to integrate. Here, a birefringent dielectric metasurface is demonstrated, which is capable of generating Bessel beam whose polarization state continuously rotates along the propagation direction. According to the design, when a linearly polarized light illuminates on the metasurface, the outgoing light becomes linearly polarized zero-order Bessel beam, whose polarization angle changes as the propagation distance increases. Experimental measurements are successfully carried out. Such scheme may open new doors for potential applications in depth perception, microscopic detection, and so on.