Metasurface-Enabled Light-Driven Liquid Crystal Elastomer Actuators.

Soft actuators based on liquid crystal elastomers (LCEs) offer programmable shape-morphing capabilities for biomedical devices and microrobotics. However, conventional photothermal LCE actuators lack spatial selectivity in actuation, suffer from low photothermal conversion efficiency and poor wavelength versatility, which severely limit their performance, especially at the challenging 980 nm window. Here, we introduce a plasmonic metasurface strategy that enables spatially selective, high-efficiency photothermal actuation. By patterning designed gold nanostructures onto LCEs, we create programmable "hot spots" that drive localized deformations under NIR illumination. This platform achieves unprecedented combined performance at 980 nm, including high photothermal conversion efficiency, low driving power, and competitive response times, while enabling patterned actuation. Moreover, we employ photoluminescence thermography to directly visualize and quantify thermal gradients generated across the LCE film, providing crucial insights into the spatiotemporal thermal dynamics. We also provide a comprehensive analysis from nanoscale plasmonic heating to macroscopic heat transfer. By integrating metasurface patterning with photoalignment, we demonstrate diverse actuation modes, from simple 2D bending to complex 3D morphing. This work establishes a new paradigm for high-performance soft actuators, opening avenues for advanced applications in soft robotics, adaptive optics, and intelligent responsive systems.