Introducing the world’s thinnest, most efficient, broadest band, flat lens

EECS Assoc. Prof. Boubacar Kanté, his graduate students Liyi Hsu, Jeongho Ha and Jun-Hee Park, postdoctoral researcher Abdoulaye Ndao, and Prof. Connie Chang-Hasnain, have demonstrated a revolutionary, ultrathin and compact, flat optical lens that spans wavelengths from the visible to the infrared with record-breaking efficiencies.  Their paper, “Octave bandwidth photonic fishnet-achromatic-metalens,” published in Nature Communications, is the first time a photonic system with the entire rainbow has been proposed and demonstrated with efficiencies larger than 70% in the visible-infrared region of the spectrum.  Attempts to make traditional lenses flatter and thinner, so that they can be deployed in increasingly smaller applications, have been hampered by the way that lens curvature and thickness are used to direct light.  The Fishnet-Achromatic-Metalens (FAM) utilizes a complex “fishnet” of tiny, connected waveguides with a gradient in dimensions, which focuses light on a single point on the other side of the lens, regardless of the incident wavelength.  As the world’s thinnest, most efficient, and broadest band, flat lens, its use in applications like solar energy, medical imaging, and virtual reality, is just the beginning.  As Kanté explains, “We have overcome what was regarded as a fundamental roadblock.”  One idea for a possible implementation would be to integrate the miniature lens into microrobots being developed at the Berkeley Sensor & Actuator Center (BSAC).