Active laser detection technique based on cat-eye effect has the advantages of long detection distance and high orientation precision. The reflected light intensity of the cat-eye system is 2–4 orders of magnitude higher than the general diffuse reflection intensity. Thus, laser active detection technology based on the cat-eye effect may realize accurate aiming and directional confrontation. However, few studies focus on the influence of a multi-band laser with a large incident angle on the echo distribution.

In a study published in Optics Express, a research group led by Prof. CHEN Fei and his Doctoral student LV Zhe from Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS) proposed a three-dimensional echo distribution calculation model of an obliquely incident dual-band laser based on the Collins diffraction integral formula and aperture function expansion as the sum of complex Gaussian functions.

To construct a more efficient and accurate model for detecting targets utilizing both visible and far-infrared bands, this paper proposes to develop a four-interval theoretical model for dual-band cat-eye target echo detection.

Moreover, the paper would conduct a detailed quantitative analysis of the impacts of various variables on the echo spot, including incident wavelength, defocus amount, and incident angle. Corresponding dual-band echo spot detection experiments and theoretical results are compared and analyzed. Echo spot images are collected from experimental and theoretical results, and corresponding data such as echo power, echo spot radius, centroid position, and centroid target-missing quantities amount are extracted to quantitatively study the echo spot and its influencing factors.

Therefore, compared with my previous published articles, this study addresses the lack of quantitative analysis of variable factors, such as incident wavelength defocus and incident angle, in laser active detection based on the cat-eye effect. The theoretical and experimental results of this paper can provide a theoretical basis for extracting working band information of cat-eye targets and predicting the trajectory of moving cat-eye targets in laser active detection, thus achieving real-time tracking and detection recognition.

The theoretical and experimental conclusions proposed in this paper can effectively obtain the working waveband information of cat eye targets by analyzing the distribution of echo light fields during multi-band detection, providing a theoretical basis for predicting trajectories and achieving real-time continuous tracking and detection of high-speed moving cat-eye targets.