Quantum state measurement using phase-sensitive amplification in a driven three-level atomic system

Abstract

Phase-sensitive amplification in a three-level atomic system exhibits interesting features. For example, in the zero-detuning limit and for sufficiently strong driving field, this system becomes an ideal parametric amplifier, whereas, for a weak driving field it is a phase-insensitive amplifier [Ansari et al., Phys. Rev. A 41, 5179 ( 1990)]. In this paper, we show that this system could be used to measure the quantum state of the radiation field inside a cavity. To reconstruct the quantum state, we amplify it through a three-level atomic system and in the parametric limit, when noise in both the quadratures approaches to zero measure the amplified field quadrature, The complete quadrature distribution is obtained by measuring the quadratures for different values of the driving field phases. The inverse Radon transformation is then employed to reconstruct the original quantum state. Our scheme is insensitive to the problems associated with nonunit detector efficiency in homodyne detection measurement.