Sun Wenbo, Hu Yongxiang, Weimer Carl, Hou Weilin, Lee Tsengdar, Videen Gorden, Baize Rosemary R
Science Systems and Applications Inc., Hampton, VA 23666, USA.
Department of Astronomy and Space Science, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104, Korea.
J Quant Spectrosc Radiat Transf. 2018 Nov;220:119-122. doi: 10.1016/j.jqsrt.2018.09.016.
Lasers with orbital angular momentum (OAM) have potential applications in communication technology, manipulation of particles, and remote sensing. Because of its unusual light-scattering properties, the OAM laser's interaction with a molecular atmosphere must be studied to ensure that it is not lossy for communication or remote-sensing applications that involve its transmission through an atmospheric environment. In this study, the finite-difference time-domain (FDTD) method [21] is applied to calculate the light scattering of the purely azimuthal (the radial mode number is assumed to be zero) Laguerre-Gaussian (LG) beams with OAM by very small dielectric particles. Not like Lorentz-Mie solutions, the FDTD method can calculate for particles off the central axis of the LG beam. It is found that when the particles are very small, and the topological charge number of the OAM of a laser is not extremely large, the laser's OAM has little effect on the scattering phase function. This suggests that Rayleigh theory can be applied directly to calculate the light scattering by atmospheric molecules. The transmission of a laser beam with OAM in a molecular atmosphere is not different from that of a regular Gaussian beam.
具有轨道角动量（OAM）的激光在通信技术、粒子操控和遥感领域具有潜在应用。由于其独特的光散射特性，必须研究OAM激光与分子大气的相互作用，以确保其在涉及通过大气环境传输的通信或遥感应用中不会产生损耗。在本研究中，采用时域有限差分（FDTD）方法[21]来计算具有OAM的纯方位角（假设径向模数为零）拉盖尔 - 高斯（LG）光束被非常小的电介质粒子的光散射。与洛伦兹 - 米氏解不同，FDTD方法可以计算偏离LG光束中心轴的粒子。研究发现，当粒子非常小且激光OAM的拓扑电荷数不是极大时，激光的OAM对散射相位函数影响很小。这表明瑞利理论可直接用于计算大气分子的光散射。具有OAM的激光束在分子大气中的传输与普通高斯光束的传输没有差异。
