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.
Balancing efficiencies by squeezing in realistic eight-port homodyne detection / J.-P. Pellonpaa, J. Schultz, M. Paris. - In: PHYSICAL REVIEW A. - ISSN 1050-2947. - 83:4(2011), pp. 043818.043818.1-043818.043818.7.
|Titolo:||Balancing efficiencies by squeezing in realistic eight-port homodyne detection|
PARIS, MATTEO (Ultimo)
|Settore Scientifico Disciplinare:||Settore FIS/03 - Fisica della Materia|
|Data di pubblicazione:||2011|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1103/PhysRevA.83.043818|
|Appare nelle tipologie:||01 - Articolo su periodico|