Optical photons are excellent quantum information carriers, but weak optical nonlinearity poses significant challenges to these systems’ scalability and computational capabilities. Currently, only probabilistic methods can achieve nonlinear quantum operations crucial for universality and fault tolerance, restricting the clock speed and making it challenging to scale due to significant resource overhead. Ultrafast quantum nanophotonics with second-order optical nonlinearity presents a potential solution to overcome these challenges. In this talk, we will discuss recent experimental advances, including the on-chip generation and measurement of ultra-broadband squeezed states and all-optical realizations of switching and nonlinear functions in an emergent thin-film lithium niobate platform. We further delve into how enhanced optical nonlinearity can enable novel functionalities such as photon-number-resolving measurements and deterministic quantum state engineering, offering a practical path to scalable, fault-tolerant quantum information processors at room temperature.
