Over the past decades, engineers have introduced numerous technologies that rely on light and its underlying characteristics. These include photonic and quantum systems that could advance imaging, communication and information processing.

A key challenge that has so far limited the performance of these new technologies is that most materials used to fabricate them have a weak optical nonlinearity. This essentially means that they do not strongly change in response to light of different intensities.

A strong optical linearity is of crucial importance for the development of ultrafast optical switches, devices that can control either light or electrical signals by modulating the properties of a light-based signal (e.g. its intensity or path). Notably, these switches are central components of fiber optics-based communication systems, photonic devices and quantum technologies.