Metasurfaces etched into 2D crystals boost nonlinear optical effects at nanoscale

In January, a team led by Jim Schuck, professor of mechanical engineering at Columbia Engineering, developed a method for creating entangled photon pairs, a critical component of emerging quantum technologies, using a crystalline device just 3.4 micrometers thick.

Now, in a paper published in Nature Photonics in October, Columbia Engineers have shrunk nonlinear platforms with high efficiency down to just 160 nanometers by introducing metasurfaces: artificial geometries etched into ultrathin crystals that imbue them with new optical properties.