New signal processing boosts quantum light detection efficiency

Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have developed a signal processing method to substantially improve the efficiency of detecting ultrafast quantum states. By optimizing how quadrature outcomes are extracted from detector signals, the team achieved a significant increase in the signal-to-noise ratio during homodyne detection. The work centers on analyzing the autocorrelations of shot noise and electronic noise to determine the optimal weight for signal processing. These results highlight the importance of optimized signal processing for efficient quantum measurements. This optimization directly addresses a challenge in measuring continuous-variable quantum states, yielding a substantial increase in the signal-to-noise ratio and, consequently, improved detection efficiency.…