Atmospheric pollutant poses a direct threat to human health. The prevalent aerosolic particles in the atmosphere can carry and spread various pathogens, endotoxins and allergens, potentially giving rise to allergies and respiratory disorders. Most of the traditional methods for monitoring aerosolic pollution require sampling and analysis at fixed stations, with limited monitoring ranges. Remote monitoring approach based on light detection and ranging (LiDAR) technology has offered an alternative way. The transmission attenuation characteristics of laser in the atmosphere is one of the main factors affecting the detection performance of LiDAR. Especially in a high-humidity environment, the effective detection range is notably reduced by the low atmospheric visibility. Here, we introduce a theoretical model for a marine atmospheric pollutant detection LiDAR utilizing both fluorescence and Mie scattering techniques. The MODTRAN software is used to calculate the atmospheric transmittance in a high-humidity environment. The detection performance of the LiDAR system is subsequently simulated and analyzed under various marine atmospheric conditions ranging from coastal to offshore environments by incorporating historical data from the National Meteorological Center of China. The results presented here offer valuable insights into optimizing LiDAR technology for enhanced monitoring of marine atmospheric pollutants.
Long-range detection LiDAR is a promising tool for online air quality monitoring in atmospheric research. Monitoring from a distance enables wide area coverage, allowing for the tracking of all changes and the increase of available response time compared with point detection methods. Here, we introduce a multi-channel laser-induced fluorescence LiDAR, achieving remote detection of environmental pollution and identification of organic pollutants based on scattering and fluorescence. A mathematical and physical model that encompasses the entire process of laser transmission in the atmosphere, interactions between aerosol particles and laser light, and the analysis of received echo signals is presented. Followed by a performance simulation and evaluation that takes into account the maximum detection distance. The results discussed herein can serve as a reference for future application of LiDAR in monitoring of environmental pollution.
Considerable interest has been exhibited in characteristics of vortex beams due to their importance in basic science and some attractive applications. The general expression of vortex beams with limited aperture is developed, and the analytical formulas for the average intensity distribution of annular vortex beam with limited aperture in the turbulent atmosphere are derived based on the extended Huygens-Fresnel principle. Under the H-V 5/7 turbulence model, the characteristics of the annular vortex beams with limited apertures propagation through the turbulent atmosphere in a slant path are analyzed in the present paper.
A typical model of the flattened-vortex beam propagating through the turbulent atmosphere in a slant path is established, and the analytical formulas of the average intensity distribution at the observation plane are derived based on the extended Huygens-Fresnel principle. Under the H-V 5/7 turbulence model, the characteristics of the average intensity distribution at the observation plane are investigated, and the influences of the optical topological charge, the propagation distance, and the zenith angle of the propagation path are numerically analyzed.
Improving performance of beam uplink propagation in the relay mirror system has become a very lively area of scientific
research. In recent years, many methods were proposed. But most related researches only concerns power coupling
efficiency. We propose that both power coupling efficiency and the non-uniformity of the received beam should be
considered. Model of the relay mirror system is established. With this model, damage effect of the system is theoretically
analyzed in detail. Performances of uplink propagation with optimizations using different evaluation functions are
calculated. Results show that uplink propagation with optimization using power coupling efficiency as the evaluation
function can't get the optimal performance. For the 25km-altitude relay mirror system, performance of uplink
propagation decreases instead of increases with optimization using power coupling efficiency as the evaluation function.
The coming results show that taking the product of power coupling efficiency and the influence factor induced by the
non-uniformity of the received beam as the evaluation function of the uplink propagation process is reasonable.
The laser relay mirror technique has been under extensive research in recent years. The concept and the working process
of the relay mirror system are analyzed in this paper. The model of the relay mirror system is established, the effect on
1km-altitude target with 500 m/s flying speed of the relay mirror system and the conventional ground-based laser system
are calculated respectively. Obtains that the maximum coverage range of the ground-based laser system is 2.0 km and the
maximum coverage range of the relay mirror system is 23.2 km. The relay mirror can largely open up the coverage range
of the laser system and strengthen the attacking ability of the ground-based laser.
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