arXiv:1012.2794 · Physical Review A

Balancing efficiencies by squeezing in realistic eight-port homodyne detection

Juha-Pekka Pellonpää, Jussi Schultz, Matteo G. A. Paris

Published Apr 15, 2011• 9 citations

Abstract

We address measurements of covariant phase observables (CPOs) by means of realistic eight-port homodyne detectors. We do not assume equal quantum efficiencies for the four photodetectors and investigate the conditions under which the measurement of a CPO may be achieved. We show that balancing the efficiencies using an additional beam splitter allows us to achieve a CPO at the price of reducing the overall effective efficiency, and prove that it is never a smearing of the ideal CPO achievable with unit quantum efficiency. An alternative strategy based on employing a squeezed vacuum as a parameter field is also suggested, which allows one to increase the overall efficiency in comparison to the passive case using only a moderate amount of squeezing. Both methods are suitable for implementation with current technology.

DOI: 10.1103/physreva.83.043818

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