Photomechanical meta-molecule array for real-time terahertz imaging

Real-time terahertz imaging has been realized by coupling an array of terahertz-absorbing meta-molecules to heat-sensitive cantilevers. Imaging using terahertz waves, which lie between microwaves and infrared waves in the electromagnetic spectrum, is promising for many applications, including airport security and medical diagnosis. But most terahertz detectors have to be scanned, making it time-consuming to obtain images. Now, Yongzheng Wen of Peking University, China, and co-workers have devised a terahertz detector capable of obtaining images in real time in three steps. A 128×128 array of meta-molecules absorbs terahertz waves and converts them into heat, which causes cantilevers attached to the meta-molecules to mechanically deform. These deflections are then optically read out. The team demonstrated their detector by using it to capture images of various objects and a 20-frames-per-second video.