Northeastern Voice

New micro-lens to improve electronic devices

Srinivas Sridhar

Northeastern physics researchers have created a new micro-lens that focuses infrared light at telecommunication frequencies — potentially leading to innovations in personal electronic devices.

Distinguished Professor Srinivas Sridhar, chair of physics, and his team at the university’s Electronic Materials Research Institute say their micro-lens has the shortest focal length ever achieved, focusing an infrared beam to a spot just 12 micrometers away from the surface.

The two-dimensional meta-material micro-lens, which uses the negative refractive index, was created by nano-engineering a photonic-crystal substrate into a multi-layered semiconducting wafer.

The micro-lens focuses infrared light at the limit of diffraction laws. In addition, the location of the focused light image is very sharp with little blurring.

“In order to go to the next level and create more efficient electronics, such as digital cameras, we need to explore ways to make things smaller,” said Sridhar. “This research shows that it is possible to create smaller, ultra-compact infrared optical components that can be integrated into existing semiconductor technologies while not sacrificing image quality.”

In addition to Sridhar, researchers involved with this project include Bernard Didier F. Casse, Wentao Lu and Yongjiang Huang, all of Northeastern’s physics department.  The report of their work was published in the Aug. 7 edition of the journal “Applied Physics Letters.”

This work was also supported by the Air Force Research Laboratories and the National Science Foundation.