Quantum optics is a field that relies heavily on experimental techniques to study the interactions between light and matter at the quantum level. Techniques such as spontaneous parametric down-conversion (SPDC) generate entangled photon pairs, which can be manipulated using various methods including quantum gates. Interferometry is also used to study the behavior of light and its interactions with matter by splitting a light beam into two or more paths and recombining them to produce an interference pattern.