Roadmap for optical meta-devices based on metamaterials

Abstract

Abstract. This roadmap presents a comprehensive overview of recent advances and future directions in optical meta-devices based on metamaterials and metasurfaces. The roadmap first reviews the fundamental principles of flat optics and metasurface engineering, followed by recent progress in metalenses and compact flat imaging systems. Wavefront engineering techniques and Huygens metasurfaces are discussed as key approaches for achieving complete optical field manipulation. The roadmap further highlights the emerging role of inverse design and artificial intelligence in automating the optimization of meta-atoms and improving device performance beyond the limitations of conventional design methodologies. In addition, active and reconfigurable metasurfaces enabled by tunable materials, micro-electromechanical system platforms, and electrical control technologies are surveyed for the realization of adaptive optical systems. Nonlinear metasurfaces and high-Q quasi-bound states in the continuum are also reviewed with emphasis on enhanced light–matter interactions, nonlinear optical responses, and ultrasensitive sensing applications. Furthermore, recent developments in space-time modulation and nonreciprocal metasurfaces are introduced as a promising framework for spatiotemporal wave manipulation and nonreciprocal propagation. Expanding the scope of applications, multifunctional metasurfaces for holography, AR/VR, and quantum imaging are discussed together with meta-integrated devices combining metasurfaces with photodetectors, emitters, and thermal management systems. Finally, scalable manufacturing technologies and system-level integration strategies, including CMOS-compatible fabrication and fiber-optic integration, are examined to address the transition from laboratory demonstrations to practical and commercial optical systems. By integrating these interconnected topics, this roadmap provides both a concise summary of the current state-of-the-art and a strategic perspective for the future development of next-generation optical meta-devices.