Space and Time Modulations of Light with Metasurfaces: Recent Progress and Future Prospects

Abstract

In this Perspective, we discuss the different opportunities offered by time-modulated metasurfaces for dynamic wavefront engineering and space-time photonics. Efforts in codesigning a photonic response while taking into careful consideration the switching/tuning mechanisms, including thermal, electronic, optical, chemical, and mechanical actuation, are essential for achieving sufficient amplitude, phase, and polarization modulation. Here, we examine in detail how the key enabling photonic technologies currently available and relying on similar tuning mechanisms can be applied for the conception of tunable metasurfaces. We review the latest developments and discuss the advantages and limitations of each approach, providing the reader with a clear vision of the current state of the art in active metasurfaces. We also address the readiness of each technological approach to drawing short- and long-term application perspectives. Finally, we discuss perspectives for spatiotemporal metasurface modulation opening new horizons toward unlimited wavefront engineering capabilities.

Opportunities and Challenges for Large-Scale Phase-Change Material Integrated Electro-Photonics

“…Recent works have demonstrated reliable multibit operations, large capacity, and reliability. ,, Exploiting the reliable multibit operation, researchers also used PCMs to realize neuromorphic optical computing, ,− potentially overcoming the von Neumann bottleneck in modern computer architectures. Other than applications in integrated photonics, recent years have also seen significant advancements in using PCMs for active meta-optics. ,− Meta-optics can implement arbitrary phase profiles through engineering subwavelength scale scatterers (or meta-atoms). By incorporating PCMs in these meta-atoms, the phase profile can change significantly once the microstructural phase is switched.…”

A review of tunable photonics: Optically active materials and applications from visible to terahertz

“…It is noteworthy that CMOS technology could be a cornerstone for the mass production of dynamic photonics based on the highly mature LCD technology. For example, Lumotive Inc. produces an ultra-compact light detection and ranging (LiDAR) system based on LC through conventional 0.13 μm CMOS semiconductor foundry with a Himax Inc. semiconductor experts ( Kim et al., 2021c ; Mikheeva et al., 2022 ). However, they have some limitations to be resolved including the slow modulation speed (microsecond level) and large structural volume.…”

Recent Advances in Tunable Metasurfaces: Materials, Design, and Applications

“…Although there are several review articles on tunable metasurfaces in recent years, − given its rapid development, we believe a comprehensive review of the latest achievement on design methods, active materials, and applications of tunable metasurfaces will be beneficial to the community. This article briefly reviews the progress and achievement in the past decade but focuses on the recent two to three years.…”