Arbitrary Tuning of Polarization and Circular Dichroism Based on Guided Mode Resonance of Achiral Dielectric Metasurfaces

Abstract

Metasurfaces designed for dynamically modulation of strong circular dichroism (CD) hold significant potential in engineering fields such as polarization detection, spectral sensing, and optical communication. Such metasurfaces often require precise and complex chiral structural designs and activation, which limit their practical applications. Here, a simple and achiral dielectric metasurface based on guided mode resonance (GMR) is proposed and experimentally demonstrated for achieving arbitrary polarization and CD tuning. A truncated dielectric grating (TDG) structure involving only three parameters is employed to construct a complete and continuous variation of polarization modes around Γ-point. The proposed achiral metasurface can achieve a near-perfect CD peak of 0.97 at 1.55 µm and also continuous tuning of CD from −0.97 to 0.97 by simply changing the azimuth angle of the TDG at a designed incident angle. Furthermore, under a linearly polarized incidence, the output polarization state can be arbitrarily tuned from linear to either of two orthogonal circular polarization. The proposed metasurface with minimalist achiral and dielectric structure that can significantly reduce both the design and the fabrication complexity provides a novel paradigm for various polarization manipulation in fields of spin-selective wavefront shaping, angular sensing, optical security, and other dynamic chiral optical devices.