In the $20 billion market for AR/VR glasses, consumers are looking for glasses that are compact and easy to wear, delivering high-quality imagery with socially acceptable optics that don't look like "bug eyes." University of Rochester researchers at the Institute of Optics have come up with a novel technology to deliver those attributes by imprinting freeform optics with a nanophotonic optical element called "a metasurface.”
The metasurface is a forest of tiny, silver, nanoscale structures on a thin metallic film that conforms, in this advance, to the freeform shape of the optics — realizing a new optical component the researchers call a metaform. The metaform is able to defy the conventional laws of reflection, gathering the visible light rays entering an AR/VR eyepiece from all directions, and redirecting them directly into the human eye.
Nick Vamivakas, a professor of quantum optics and quantum physics, likened the nanoscale structures to small-scale radio antennas. "When we actuate the device and illuminate it with the right wavelength, all of these antennas start oscillating, radiating a new light that delivers the image we want downstream."
"Metasurfaces are also called 'flat optics' so writing metasurfaces on freeform optics is creating an entirely new type of optical component," says Jannick Rolland, the Brian J. Thompson Professor of Optical Engineering and director of the Center for Freeform Optics.
Adds Rolland, "This kind of optical component can be applied to any mirrors or lenses, so we are already finding applications in other types of components" such as sensors and mobile cameras.
In creating the new glasses, the researchers use a freespace optical combiner to direct the visible light entering the AR/VR glasses to the eye. However, when the combiner is part of freeform optics that curve around the head to conform to an eyeglass format, not all of the light is directed to the eye. Freeform optics alone cannot solve this specific challenge. To address this, the researchers