Phase measurement at the Heisenberg limit with three photons
Haibo Wang, Takayoshi Kobayashi · Physical Review A · 2005
We describe an interferometer which is capable of measuring phase at a Heisenberg limit of $1∕3$. The proposed interferometer, which consumes three indistinguishable photons, consists of two beam splitters with two-third reflectivity and two mirrors. It is shown that the oscillation period of the quantum interference is three times shorter than in the classical case and the interference visibility is 100%. A de Broglie wavelength given by ${\ensuremath{\lambda}}_{0}∕3$ can then be observed in this scheme, where ${\ensuremath{\lambda}}_{0}$ is the wavelength of a single photon. Compared with similar phase measurements [Mitchell et al., Nature (London) 429, 161 (2004); Walter et al., ibid. 429, 158 (2004)] by multiphoton maximally entangled states (MES), a three-photon MES is not generated in our proposal.