Researchers have integrated two technologies widely used in applications such as optical communications, bio-imaging, and Light Detection and Ranging (LiDAR) systems to create a new infrared light-focusing system that combines the best features of both technologies while reducing the size of the optical system.
A metasurface-based lens was crafted on top of a microelectromechanical system (MEMS) platform.
Metasurfaces can be structured at the nanoscale to work like lenses. These lenses are rapidly finding applications because they are much thinner and less bulky than existing lenses and can be made with the same technology used to fabricate computer chips. The MEMS are small mechanical devices that consist of tiny, movable mirrors. The device measures 900 microns in diameter and 10 microns in thickness (a human hair is approximately 50 microns thick).
In the technologically merged optical system, MEMS mirrors reflect scanned light, which the metalens then focuses without the need for an additional optical component such as a focusing lens. The challenge was to integrate the two technologies without hurting their performance. The eventual goal would be to fabricate all components of an optical system — the MEMS, light source, and metasurface-based optics — with the same technology used to manufacture electronics today. Then, in principle, optical systems could be made as thin as credit cards.
These lens-on-MEMS devices could advance the LiDAR systems used to guide self-driving cars. Current LiDAR systems, which scan for obstacles in their immediate proximity, are several feet in diameter and require large, bulky lenses as well as mechanical objects to move them around, which is slow and expensive.