Multi-mode Coherent Detection Ghost Imaging Lidar and Vibration-Mode Imaging

Coherent detection ghost imaging lidar (CD-GI lidar) integrates ghost imaging with coherent detection, thereby achieving enhanced anti-interference and phase-resolved imaging capability. Here, we propose a bucket-detector-based multi-mode coherent detection scheme for CD-GI lidar, where the reflected multi-mode light fields are coherently mixed with a single-mode local oscillator (LO) at the bucket detector photosensitive plane. The bucket-detector-based multi-mode CD-GI lidar system breaks the constraints of Siegman antenna theorem by utilizing field correlation to decouple the reflected multi-mode light fields and reconstructs the spatial distribution of targets’ vibration modes. Theoretical analysis of the bucket-detector-based multi-mode CD-GI lidar system is presented in this work, and its feasibility is verified through a series of experiments.

💡 Research Summary

This paper introduces a novel coherent‑detection ghost‑imaging lidar (CD‑GI lidar) architecture that leverages a bucket detector to collect the multimode light reflected from a target and mixes it with a single‑mode local oscillator (LO) to generate an intermediate‑frequency (IF) signal. By exploiting field‑correlation processing rather than simple intensity correlation, the system overcomes the conventional Siegman antenna theorem limitation, which normally forces a large detector to behave as a single‑mode receiver and thus lose spatial‑mode information.

The transmitter consists of a narrow‑linewidth laser that is first chirped by an electro‑optic modulator (EOM) for range resolution, then frequency‑shifted by an acousto‑optic modulator (AOM). A digital micromirror device (DMD) imposes a sequence of binary spatial patterns, thereby creating a spatiotemporally modulated illumination field. The target is modeled by a complex reflectivity combined with a time‑varying phase term that represents micro‑vibrations. After propagation, the reflected field passes through a receiving lens and impinges on the photosensitive area of a balanced bucket detector. There, it interferes coherently with the LO, and the resulting photocurrent is proportional to an integral of the product A₁(ρₒ,ρ_d)·cos