Science and Technology Daily (Reporter Zhang Mengran) – Researchers at Georgia Institute of Technology have developed a biomimetic soft lens that can automatically adjust its focus based on ambient light intensity, just like the human eye. This achievement demonstrates the broad prospects of light-driven soft materials in building adaptive vision systems, autonomous soft robots, smart medical devices, and next-generation wearable technologies. The relevant research results were published in the latest issue of the journal *Science Robotics*.

This device, called a photoresponsive hydrogel soft lens (PHySL), is made of a hydrogel embedded with light-absorbing graphene oxide, with a microlens at its center. When light shines on it, the graphene oxide absorbs the light energy and generates heat, causing the hydrogel to shrink, thereby stretching the central lens, changing its curvature, and achieving pupil dilation and focal length extension. When the light intensity decreases, the gel cools and returns to its original shape, and the lens also retracts to its initial form. The entire process requires no external power source or mechanical drive.

This design overcomes the limitations of traditional biomimetic optical systems that rely on electronic components or rigid motors, achieving true autonomous adjustment. Researchers integrated PHySL into a conventional bright-field microscope to perform high-resolution imaging of various biological samples, clearly capturing the fine hairs on ant legs, the lobed structures on pollen grain surfaces, the claw-like structures on tick legs, and the minute gaps between individual fibers in fungal samples. The image quality obtained is comparable to that obtained using standard microscope objectives.

Experiments also show that PHySL can automatically adjust its focus under natural lighting conditions, making it suitable for dynamic imaging of multi-layered samples. When integrated into a fiber optic imaging system, the lens can maintain a clear focus on the target even under varying illumination conditions.

This innovation represents the latest achievement in the rapidly developing field of light-driven soft materials. These materials can directly convert light energy into mechanical deformation, with hydrogels, liquid crystal elastomers, and carbon-based composites being research hotspots and applicable to the construction of microrobots and artificial muscles. Graphene oxide, due to its broad-spectrum absorption capacity and efficient photothermal conversion performance, is often used as a "photothermal engine" embedded in polymers or hydrogels to achieve remote, non-contact, precise actuation. PHySL cleverly combines the photothermal effect of graphene oxide with the thermal response characteristics of hydrogels to construct an intelligent optical system capable of autonomously sensing and responding to ambient light.