Enhancing signal-to-noise ratio of vortex beam detection under cloud and fog conditions by combining spatial distribution and polarization information

Vortex beams carry orbital angular momentum (OAM) and exhibit a ring-shaped intensity distribution, adding a new dimension compared to Gaussian beams. In cloudy and foggy environments, using vortex beams for detection and imaging can partially improve the signal-to-noise ratio (SNR) affected by backscattering compared to Gaussian beams. However, the improvement is limited at high concentrations. We introduce a novel approach to improve the SNR of vortex beam detection under these conditions. First, we utilized a ring filter for preliminary noise reduction, then applied polarization information to divide the data into different polarization directions. We then performed weighted summation on the one-dimensional photon counting echo data from these directions to further reduce noise. Simulation results demonstrated that this method improved SNR across various parameters. Specifically, at low reflectivity, the peak signal-to-noise ratio (PSNR) increased from 0.333 to 2.14, improving ranging accuracy. In imaging, the SNR of the processed range profile rose from 9.86 dB to 15.6 dB, and the structural similarity index (SSIM) improved from 0.590 to 0.894, indicating enhanced image quality. Therefore, our method effectively enhances both ranging accuracy and imaging quality of vortex beams under cloud and fog conditions, with potential applications in fields such as remote sensing.