One photon in an open box: The Michelson interferometer

Fuyuan Wang, Bao‐Sen Shi, Guang‐Can Guo

Satoru Odate, Toshiki Kobayashi, Haoyang Wang

Seung‐Jin Yoon, Cong T. Trinh, Kwang-Geol Lee

Coherence length (time) is a key parameter in many classical and quantum optical applications. Two interferometers – Michelson and Young’s double-slit – are used to characterize the temporal coherence of single photons emitted from single terrylene molecules. For quantitative analysis, a dispersion-related distortion in the interference pattern of a Michelson interferometer is carefully corrected by a simple dispersion compensation. Additionally, it has been demonstrated that Young’s interferometer can be used in temporal coherence studies at the single photon level with high accuracy. The pros and cons of the two systems are discussed. The measured coherence lengths in the two systems are consistent with one another under the self-interference interpretations.

Ray LaPierre

Chaoping Wei, Chuting Xu, Qi Li

Power recycling techniques are usually used to improve the phase sensitivity of interferometers by reusing the input light energy, and can beat the shot noise level. Recent studies have demonstrated that the phase sensitivity of the interferometer is significantly improved via the addition of a recycling cavity, that is, coupling the interferometer with an external optical device. This study reviewed such types of interferometers named Grover-Michelson interferometers (GMI), and discusses their phase sensitivity with coherent states as inputs. Subsequently, a detailed comparison in terms of the scale of 1/ N and the standard quantum limit (SQL) is presented. The results demonstrate that the phase sensitivity of GMI improved owing to the power recycling and exceeded the value of 1/ N . Further, we proposed a modified Grover-Michelson interferometer (MGMI) with two input ports and examined its phase sensitivity with single photon or coherent states, respectively. Finally, in the presence of photon losses, we investigated the phase sensitivity of the four different interferometers, including MGMI, GMI, Mach-Zehnder interferometer (MZI), and SU(1,1) interferometer (SU(1,1)I), and conducted detailed comparisons. The results of this study indicated that the phase sensitivity of MGMI significantly improved owing to the increase in input energy, and MGMI exhibited the strongest robustness against photon number loss. These theoretical results are expected to facilitate improvements in interferometers and the detection of weak signals.

P. Hariharan