Three-dimensional echo light field analysis for dual-band laser active detection of a cat-eye optical system

Laser active detection technology utilizing the cat-eye effect provides rapid response, precise positioning, and long detection distances. However, current research mainly focuses on active detection within a single visible or near-infrared band, lacking quantitative analyses of the echo spot. In this paper, a four-interval theoretical model for dual band cat-eye target echo detection was constructed using matrix optics theory and Collins diffraction integration method. Dual-band echo detection experiments were conducted using 10.6 um far-infrared waves and 532 nm visible light waves, also the power, radius, and target-missing quantities of the echo spots were collected and quantitatively compared with the theoretical results. Results indicate that, due to the diffraction limit's effect on the distribution of the echo field, the echo power of far-infrared band detection is smaller than that of visible light band detection. The impact on the light spot caused by the positive and negative defocus values is asymmetric, with positive defocus having a lower impact on the echo spot than negative defocus at the same value. A weak positive defocus value that minimizes the radius of the echo spot and maximizes the echo power exists, with the value of weak positive defocus varying between detection bands. A linear relationship exists between the incident angle of the detection laser and the deviation of the echo spot. These findings provide a foundation for extracting working band details, predicting the motion trajectory of moving cat-eye targets, and achieving real-time tracking and detection recognition during laser active detection. & COPY; 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

In this study, a four-interval theoretical model for dual-band cat-eye target echo detection was constructed using matrix optics theory and Collins diffraction integration method. The experiment was conducted using 10.6 um far-infrared waves and 532 nm visible light waves, and the collected data of echo power, radius, and target-missing quantities were compared with theoretical results. The findings provide insights into the distribution of the echo field, the impact of defocus values on the echo spot, and the relationship between incident angle and echo spot deviation, which are important for laser active detection and tracking of moving cat-eye targets.