Quantum and nonlinear optics explores how light interacts with matter under extreme or finely controlled conditions. This field bridges quantum mechanics and photonics, studying how individual photons behave and how intense light fields can drive nonlinear responses in materials. Research spans from understanding the quantum nature of light and its use in secure communication, sensing, and computation, to investigating ultrafast and high-intensity optical phenomena that reveal new physics on the shortest timescales. Together, these approaches advance both fundamental science and technologies shaping the future of quantum information, ultrafast lasers, and optical materials.