Cover story: Zhao SQ, Fan YC, Yang RS et al. Smart reconfigurable metadevices made of shape memory alloy metamaterials. Opto-Electron Adv 8, 240109 (2025)

Metamaterials with tailored resonant elements provide a revolutionary platform for controlling light and electromagnetic wave at the subwavelength scale. However, most predesigned metamaterials can only work within a fixed narrow-frequency band for specific function, which limits many practical applications. Inspired by the smart controllable re-shape processing under certain stimulus of shape memory alloys (SMAs), Professor Yuancheng Fan and Professor Fuli Zhang from Northwestern Polytechnical University in collaboration with Professor Yongzheng Wen and Professor Ji Zhou from Tsinghua University reported a type of miniaturized tunable metamaterial device that combines the thermal tenability of SMA with the extraordinary properties of metamaterial structure. The fusion design strategy integrating metamaterials with smart natural materials allows for a more efficient utilization of the intrinsic properties of materials and for the novel functionalities emerging from structural design. With the new SMAs based metadevice, an experimental transmission enhancement of 126 times is achieved for microwaves to pass through a sub-wavelength aperture. Upon thermal excitation, the metamaterial can reconfigure its shape, allowing for non-contact tunability of both transmission frequency and amplitude. Additionally, they developed a dualband tunable device, showcasing high design flexibility for multifunctional integration. This research presents a novel pathway for the development of thermally tunable multifunctional meta-devices.