Wang, YuanlongYokoyama, ShotaDong, DaoyiPetersen, IanHuntington, ElanorYonezawa, Hidehiro2023-08-140018-9448http://hdl.handle.net/1885/295575IEEE Quantum detector tomography is a fundamental technique for calibrating quantum devices and performing quantum engineering tasks. In this paper, a novel quantum detector tomography method is proposed. First, a series of different probe states are used to generate measurement data. Then, using constrained linear regression estimation, a stage-1 estimation of the detector is obtained. Finally, the positive semidefinite requirement is added to guarantee a physical stage-2 estimation. This Two-stage Estimation (TSE) method has computational complexity O(nd2M), where n is the number of d-dimensional detector matrices and M is the number of different probe states. An error upper bound is established, and optimization on the coherent probe states is investigated. We perform simulation and a quantum optical experiment to testify the effectiveness of the TSE method.This work was supported in part by the Australian Research Council’s Discovery Projects funding scheme under Project DP190101566 and Project DP180101805, in part by the Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology under Project CE170100012, and in part by the U.S. Office of Naval Research Global under Grant N62909-19-1-2129. (Corresponding author: Daoyi Dong.)application/pdfen-AU© 2021 IEEEQuantum systemquantum detector tomographytwo-stage estimationcomputational complexity202110.1109/TIT.2021.30625962022-07-24