Flat Optical Rotator Enabled by Conformal Mapping

ABSTRACT Flat optics has been recognized as a key player in the field of optics. Notably, blazed gratings and flat lenses can replace traditional bulky optical elements to achieve light field translation and scaling, significantly enhancing system compactness and portability. However, light field rotation—another fundamental operation—still relies on thick Dove prisms requiring internal reflections to break planar symmetry perpendicular to the propagation direction, hindering device integration. To address this challenge, we mimic the Dove prism and present a flat optical element for optical rotation inspired by conformal mapping theory, which reveals that the rotation angle of the light field is twice that of the optical rotator. Here, we design and demonstrate that this flat component can rotate light fields with arbitrary amplitude and phase distributions by any desired angle. With the advantages of universality, ultra‐compactness, and ease of integration, our work holds significant potential for applications in image processing, computer vision, and related fields, expanding the application scope of transformation optics.