Information processing is currently undergoing yet another revolution, with the rise of large-language models enabled by massive computing power. However, this remarkable progress is facing fundamental limits to keep up with the required demand. Therefore, alternative forms of computing are highly necessary for future growth and development. It has long been hypothesized that photonic integrated circuits, operating with light instead of electric charge, could pave the way to computational performance beyond the limitations of transistor miniaturization. In particular, they could operate much faster, while being much more energy efficient at the same time. One of the key bottlenecks in the development of photonic computing is the current lack of an efficient photonic counterpart of electronic transistors as universal building blocks of integrated circuits. To date, complementary approaches in photonics have been utilized for controlling the phase of light and thus its interference effects. However, they all fall short in providing an efficient and universal platform for programmable photonic circuits. In the RaPPIC project, we proposed to develop novel electro-optical gates based on atomically thin two-dimensional semiconductors as a new paradigm for the realization of universal building block of rapid and programmable photonic integrated circuitry. Using these gates, a photonic circuit can be reprogrammed at ultra-high speeds with highest phase manipulation efficiency, allowing small footprints and enabling scalability that is indispensable for leveraging the fundamental advantages of photonic computing.
