Computer-chip technology may influence future lens production, which can replace the bulky layers of traditional designs.
A flat lens, as its name suggests, has a flat shape, which allows it to offer distortion-free imaging. They are usually lightweight due to optical materials known as metasurfaces. As the metasurface’s subwavelength nanostructures create recurrent patterns, they resemble the complex curvatures that refract light. However, they do this with reduced distortion and bulk.
Although beneficial, the nanostructured devices are often static, which limits functional potential.
Federico Capasso, applied physicist at Harvard University, and Daniel Lopez, group leader of nanofabrication and devices at Argonne National Laboratory, looked to microelectromechanical systems (MEMS) to spruce up the design. Together, they developed a device that incorporates mid-infrared spectrum metalenses onto MEMS.
“Dense integration of thousands of individually controlled lens-on-MEMS devices onto a single silicon chip would allow an unprecedented degree of control and manipulation of the optical field,” says Lopez.
The team created a metasurface lens through traditional methods on a silicon-on-insulator wafer. Next, a flat lens was situated on a MEMS scanner. After the lens and the MEMS’ central platform were aligned, they were fixed together.
“Our MEMS-integrated metasurface lens prototype can be electrically controlled to vary the angular rotation of a flat lens and can scan the focal spot by several degrees,” says Lopez.
“Furthermore, this proof-of-concept integration of metasurface-based flat lenses with MEMS scanners can be extended to the visible and other parts of the electromagnetic spectrum, implying the potential for application across wider fields, such as MEMS-based microscope systems, holographic and projection imaging, lidar (light detection and ranging) scanners, and laser printing,” Lopez adds.
The full article, “Dynamic metasurface lens based on MEMS technology,” can be found in the journal APL Photonics.