The Mesoscopic Quantum Optics (MQO) group uses light to try and expose nonclassical phenomena at larger and larger energy scales. The most interesting and counter-intuitive consequences of quantum mechanics, for example superposition, wave-particle duality and nonlocality, are not part of our everyday experience of the world. We wish to find out what the scale limits are on phenomena like these, and whether they can be overcome. Our route to building large quantum system is to make large building blocks - fundamental quantum units that can be combined to build even larger systems. This approach combines sophisticated techniques in nonlinear optics, integrated optics and superconducting detectors, as well as theoretical techniques to deal with large data sets and develop protocols in this new, mesoscopic regime of quantum optics.