Sub-shot-noise-limited phase estimation via SU(1,1) interferometer with thermal states
Xiaoping Ma, Chenglong You, Sushovit Adhikari, Elisha S. Matekole, Ryan T. Glasser, Hwang Lee, Jonathan P. Dowling · Optics Express · 2018
We theoretically study the phase sensitivity of an SU(1,1) interferometer with a thermal state and a squeezed vacuum state as inputs and parity detection as the measurement. We find that the phase sensitivity can beat the shot-noise limit and approaches the Heisenberg limit, with increasing input photon number, in an ideal situation. We also consider the effect of various noises, including photon loss, dark counts, and thermal photon noise. Our results show that the phase sensitivity is below the shot-noise limit with photon loss and dark counts, but cannot beat the shot-noise limit in the presence of thermal noise.