Capasso Lab Reports Planar Metalens Designed

Julia Germaine, News Editor

Materials science has made a great leap forward toward replacing glass lenses with metasurface materials that are practical to manufacture and produce aberration-free, subwavelength-resolution images. The planar metalens could replace traditional optics in smartphones, digital cameras and microscopes to enable further miniaturization of those devices.

Light passing through the metalens is focused by the array of nanostructures on its surface. Courtesy of Capasso Lab/Harvard John A. Paulson School of Engineering and Applied Sciences.
The work was performed in the lab of physics and applied engineering professor Federico Capasso of Harvard University, whose contributions to the field of photonics, in addition to metasurface research and development, include the quantum cascade laser. Capasso discussed the technology with Photonics Media ahead of the study’s release.

“We are reporting planar lenses … that operate at visible wavelengths, and the potential, we think, is huge to replace conventional lenses in a lot of applications,” Capasso said.

The metasurface lens features towers of titanium dioxide — about 600 nm in length — which focus light based on their patterning, enabling a uniform-thickness component. In the metasurface lens, the towers bend light toward the focal point; the researchers reported the metalens achieved the same resolution and magnification as a traditional glass lens 5 to 6 cm in length.

Capasso also said that fabrication of the planar lenses could become highly cost-effective, due to the technology’s compatibility with memory and microprocessor chip foundries. The planar lenses could be fabricated similar to integrated circuits and do not require polishing or complicated post-processing steps, as glass optics do.

The video below describes the metalens and is courtesy of Science/AAAS.