Heterodyne detection enhanced by quantum correlation

TL;DR

This paper demonstrates that quantum correlation between the image band vacuum and input signal can enhance heterodyne detector performance, overcoming traditional SNR degradation in phase-insensitive measurements, with implications for space-based gravitational-wave detection.

Contribution

It introduces a method to improve heterodyne detection by utilizing quantum correlation, reducing noise and enhancing SNR in phase-insensitive detectors.

Findings

Quantum correlation reduces heterodyne detector noise.

Enhanced SNR demonstrated through noise figure calculations.

Potential applications in space-borne gravitational-wave detection.

Abstract

Heterodyne detectors as phase-insensitive (PI) devices have found important applications in precision measurements such as space-based gravitational-wave (GW) observation. However, the output signal of a PI heterodyne detector is supposed to suffer from signal-to-noise ratio (SNR) degradation due to image band vacuum and imperfect quantum efficiency. Here we show that the SNR degradation can be overcome when the image band vacuum is quantum correlated with the input signal. We calculate the noise figure of the detector and prove the feasibility of heterodyne detection with enhanced noise performance through quantum correlation. This work should be of great interest to ongoing space-borne GW signal searching experiments.