Quantum Measurements in Optics

The NATO Advanced Research Workshop on Quantum Measurements in Optics was held in Cortina d'Ampezzo, Italy, January 21-25, 1991. This workshop was attended by 70 participants from 16 different countries. The subjects discussed at this workshop concentrated on quantum measurements in optics made possible by the recent advances in the generation and detection of light with low quantum noise. These advances have occurred simultaneously with the development of atomic traps capable of trapping a single atom for a considerable period of time. The interaction of a single two level atom with the single mode of the electromagnetic field is now possible in high Q microcavities. A new field of cavity QED has developed studying the properties of Rydberg atoms in microwave cavities. At this meeting we heard the first report of an atomic interferometer where a single atom passing through the two slits exhibits wave like interference phenomena. This new field involving the transfer of momentum from photons to atoms has lead to new possibilities for quantum nondemolition measurements on an optical field. We heard suggestions for such measurements at this meeting. With the new light sources available the possibility of using low quantum noise light in optical communications becomes close to reality. The problem of the propagation of quantum light field in optical fibres was actively discussed at this meeting.