OPTICAL VON-NEUMANN MEASUREMENT

We present an optical scheme that realizes the standard von Neumann me asurement model, providing an indirect measurement of a quadrature of the field with controllable Gaussian state-reduction. The scheme is ma de of simple optical elements, like laser sources, beam splitters, and phase-sensitive amplifiers, along with a feedback mechanism that uses a Pockels cell. We show that the von Neumnnn measurement is achieved without the need of working in an ultra-short pulsed regime. (C) 1997 Elsevier Science B.V.