Abstract An interferometric detection scheme to measure optical phase shift with sensi tivity beyond the shot noise limit is proposed. The theoretical calculation shows that using the quantum correlated twin beams produced from an optical parametric amplifier as the input fields of a Mach-Zehnder interferometer, the minimum detectable phase shift will exceed the shot noise limit N-1/2 and approach the Heisenberg limit N-1. The parametric dependences of the minimum detectable phase shift on the nonlinear interaction, input photon number, and detection efficiency are shown.
Received: 03 July 1998
Revised: 07 January 1999
Accepted manuscript online:
Fund: Project supported in part by the National Natural Science Foundation of China (Grant No. 69837010), the Excellent Young Teacher Foundation from National Education Department and the Young Academic Leader Foundation of Shanxi Province, China.
Altmetric calculates a score based on the online attention an article receives. Each coloured thread in the circle represents a different type of online attention. The number in the centre is the Altmetric score. Social media and mainstream news media are the main sources that calculate the score. Reference managers such as Mendeley are also tracked but do not contribute to the score. Older articles often score higher because they have had more time to get noticed. To account for this, Altmetric has included the context data for other articles of a similar age.
