Abstract
Quantum optics is a research field with somewhat elastic boundaries. In its narrowest definition, the field is restricted to the study of those optical phenomena that can only be understood in terms of the quantum theory of light. Even this narrow scope includes a rich diversity of effects, and there have been particularly striking recent advances in the use of optical experiments to demonstrate aspects of fundamental quantum mechanical theory, such as vacuum fluctuations, the Bose-Einstein statistics, superposition states in particle interference, and violations of Bell's inequality.