Polyelectrolyte Elastomer‐Based Ionotronic Electro‐Mechano‐Optical Devices (Small 42/2025)

Optical Devices A Fresnel lens employs a series of concentric annular ridges, each of which refracts light at a specific angle and collectively produces a focused beam. Like a biological adaptive eye adjusting to light, a tunable Fresnel lens can continuously reshape itself to capture evolving scenes. The focal length increases as the zoom slider slides from “W” to “T”. More in article number 2502225, Wei Hong, Canhui Yang, and co-workers.