Analysis of laser beam propagation through atmospheric turbulence and its impact on CCD sensor intensity distribution

This study investigates the propagation of laser beams with Gaussian and Laguerre-Gaussian profiles through atmospheric turbulence and their subsequent detection by charge-coupled device (CCD) sensors. Using numerical simulations based on the Kolmogorov turbulence model, we analyze the intensity distribution of laser beams under turbulence strengths ranging from 10⁻¹⁶ to 10⁻¹² and propagation distances of 500 m to 5 km. The effects of atmospheric turbulence on photon distribution at the CCD sensor's pixels are quantified, revealing beam broadening with Full Width at Half Maximum (FWHM) increasing from 50 μm to 1.5 m under the highest turbulence conditions. Saturation and blooming phenomena are observed, with photon density exceeding 10⁶ photons/pixel in high-intensity regions. Our findings reveal that turbulence-induced distortions significantly impact beam intensity profiles, with higher turbulence levels causing up to a 70 % reduction in central intensity. Additionally, the study highlights the sensitivity of higher-order Laguerre-Gaussian modes, which exhibit up to 90 % greater broadening compared to fundamental Gaussian modes. By evaluating the impact of aperture size and f-number on beam focusing, we show that increasing the f-number from 2 to 8 reduces saturation artifacts by 60 % while spreading intensity over a larger area.