Augmented reality (AR), the technology that overlays digital content onto what users see around them in real-time, is now widely used in the retail, gaming and entertainment industries, as well as in some educational settings and learning environments. A key component of AR systems are so-called waveguide displays, transparent optical layers that guide light from a projector to the eyes of users, allowing them to see projected images integrated on top of their surrounding environment.

Waveguide displays, mounted on most AR headsets or smart glasses, are typically made up of several substrates and grating couplers (i.e., structures that diffract light into the waveguide). While these multi-layered waveguide displays are widely used, they can sometimes distort colors while also setting limits on the extent to which AR headsets or glasses can be reduced in size.

Researchers at Samsung Electronics and Pohang University of Science and Technology (POSTECH) have recently developed a new single-layer waveguide display that could enable the realization of more compact AR headsets for everyday use while also boosting the brightness and color uniformity of images seen by users. The new display, introduced in a paper published in Nature Nanotechnology, was fabricated using achromatic metagratings, arrays of rectangular nanostructures that diffract red, green and blue light at identical angles.