Quantum state measurement using phase-sensitive amplification in a driven three-level atomic system - art. no. 023811

Phase-sensitive amplification in a three-level atomic system exhibits inter esting features. For example, in the zero-detuning limit and for sufficient ly strong driving field, this system becomes an ideal parametric amplifier, whereas, for a weak driving field it is a phase-insensitive amplifier [Ans ari et al., Phys. Rev. A 41, 5179 ( 1990)]. In this paper, we show that thi s 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 t he quadratures approaches to zero measure the amplified field quadrature, T he complete quadrature distribution is obtained by measuring the quadrature s for different values of the driving field phases. The inverse Radon trans formation is then employed to reconstruct the original quantum state. Our s cheme is insensitive to the problems associated with nonunit detector effic iency in homodyne detection measurement.