海洋混合悬浮颗粒对蓝绿激光的散射特性研究

激光在水下的传输很大程度上会受到海水中悬浮颗粒物的影响，而目前对于海洋中悬浮颗粒物光散射的理论研究大多是针对单一成分的悬浮粒子而进行的，但是在真实海洋中悬浮颗粒物都是以多种成分混合的颗粒群形式而存在的，因此研究真实海洋中混合悬浮颗粒物对蓝绿激光的散射特性具有重要意义。该研究选取了对蓝绿激光传输产生较大影响的浮游藻类植物、悬浮泥沙、碎屑、悬浮气泡和矿物质这五种常见的悬浮颗粒物作为研究对象，充分考虑真实海况中这五种悬浮颗粒物的不同混合情况，构建了海水中混合球形悬浮颗粒物对蓝绿激光的散射特性模型。数值计算了海水中五种物质混合的球形悬浮颗粒物对532 nm蓝绿激光的统计平均光散射参量和平均散射相函数，分析不同混合悬浮颗粒物的混合比对平均散射、吸收和消光系数以及单次反照率随着粒子有效半径和粒子数浓度变化的影响，同时分析了不同粒子尺寸下的不同混合比对混合悬浮颗粒物的平均散射相函数随着角度变化的影响。数值结果表明，当悬浮泥沙在整个混合模型中占比越大时，平均散射系数越大，而当悬浮藻类粒子在整个混合模型中占比增大时，平均吸收系数增大，由此可知海洋中对光造成主要影响的五种常见悬浮颗粒物中，悬浮泥沙对光散射作用影响最大，悬浮藻类粒子对光吸收作用影响最大。随着悬浮颗粒物浓度的增大，混合粒子的单次反照率保持不变，由此可知混合悬浮颗粒物的平均光散射参量随着粒子浓度的增长速率是一致的。海洋中混合悬浮颗粒物的平均散射相函数随着粒子的有效半径的增大而增大，散射作用最大的混合比下的悬浮颗粒物其平均散射相函数最大，悬浮颗粒物的前向散射较强。该工作对蓝绿激光在海水中传输、信道建模，水下无线光通信的研究以及激光探测都具有重要的理论指导意义。

Scattering Characteristics of Marine Mixed Suspended Particles to Blue and Green Lasers

The transmission of laser underwater is largely affected by suspended particles in seawater. At present, most theoretical studies on the light scattering of suspended particles in the ocean are carried out on single-component suspended particles. However, suspended particles in the real ocean exist in a group of particles mixed with multiple components. Therefore, it is of great significance to study the scattering characteristics of blue-green lasers by mixed suspended particles in the real ocean. In this paper, five common suspended particles which have a greater impact on the transmission of blue-green lasers are planktonic algae, suspended sediments, debris, suspended bubbles, and minerals as the research objects. Fully considering the different mixing situations of these five suspended particles in real sea conditions, a model of the scattering characteristics of blue-green lasers by mixed spherical suspended particles in seawater is constructed. The statistical average light scattering parameters and average scattering phase function of 532 nm blue-green lasers of spherical suspended particles mixed with five seawater substances are calculated numerically. They are analyzing the influence of the mixing ratio of different mixed suspended particles on the average scattering, absorption and extinction coefficients and single albedo with the effective radius of the particles and the change of the particle number concentration. At the same time, the influence of different mixing ratios under different particle sizes on the average scattering phase function of mixed suspended particles with angle changes is analyzed. Numerical results show that the average scattering coefficient increases when the proportion of suspended sediment in the entire mixed model increases, while the average absorption coefficient increases with the proportion of suspended algae particles in the entire mixed model. It can be seen that among the five common suspended particles that have a major impact on the light in the ocean, suspended sediment has the greatest impact on light scattering, and suspended algae particles have the greatest impact on light absorption. As the concentration of suspended particles increases, the single albedo of the mixed particles remains unchanged. One can see that the average light scattering parameters of the mixed suspended particles are consistent with the increase in particle concentration. The average scattering phase function of mixed suspended particles in the ocean increases with the increase of the effective radius of the particles. The average scattering phase function of suspended particles under the mixing ratio with the largest scattering effect is the largest, and the forward scattering of suspended particles is strong. This work has important theoretical significance for the blue-green laser transmission in seawater, channel modeling, the research of underwater wireless optical communication and the laser target detection in seawater.