Optical quantum nondemolition measurements: experiments

Gerard J Milburn, Daniel F. Walls

B. C. Buchler, Ping Koy Lam, Hans‐A. Bachor +2 more

We use a stable, 5 dB, amplitude squeezed source for a quantum nondemolition (QND) experiment. The performance of our QND system is enhanced by an electro-optic feedforward loop which improves the signal transfer efficiency. At best, we measure a total signal transfer of 1.81 and conditional variance of 0.55.

J.-Ph. Poizat, Jean-François Roch, Philippe Grangier

Robert M. Shelby

The concept of quantum nondemolition (QND) measurement is outlined in the context of quantum optics. As a prototypal QND measurement scheme, the interaction of a light beam with a classical mechanical oscillator via radiation pressure is outlined. Results of QND experiments using cross‐phase modulation of two co‐propagating beams in single mode optical fibers are reviewed, and the prospects for improved schemes briefly discussed.

Marlan O. Scully, Muhammad Suhail Zubairy

Robert Bruckmeier, Hauke Hansen, Stephan Schiller

Repeated quantum nondemolition (QND) measurements for continuous optical waves were performed by combining a degenerate optical parametric amplifier and a squeezed-light beam splitter. Two-step quantum state preparation and three-beam entanglement of the individually squeezed output beams were demonstrated. The experiment is analyzed using a set of generalized criteria for nonideal individual and repeated QND measurements. The system was operated fully stabilized for up to 36 hours.