Mishchenko Michael I, Lacis Andrew A
NASA Goddard Institute for Space Studies, 2880 Broadway, New York, New York 10025-7848, USA.
Appl Opt. 2003 Sep 20;42(27):5551-6. doi: 10.1364/ao.42.005551.
We use precise T-matrix calculations for prolate and oblate spheroids, Chebyshev particles, and spheres cut by a plane to study the evolution of Lorenz-Mie morphology-dependent resonances (MDRs) with increasing asphericity of nearly spherical particles in random orientation. We show that, in the case of spheroids and Chebyshev particles, the deformation of a sphere by as little as one hundredth of a wavelength essentially annihilates supernarrow MDRs, whereas significantly larger asphericities are needed to suppress broader resonance features. The MDR position and profile are also affected when the deviation of the particle shape is increased from that of a perfect sphere. In the case of a sphere cut by a plane, the supernarrow MDRs are much more resistant to an increase in asphericity and do not change their position and profile. These findings are consistent with the widely accepted physical interpretation of the Lorenz-Mie MDRs.
我们使用精确的T矩阵计算方法，针对扁长球体、扁球体、切比雪夫粒子以及被平面切割的球体，来研究洛伦兹 - 米氏形态相关共振（MDR）随随机取向的近球形粒子非球形度增加的演化情况。我们表明，对于球体和切比雪夫粒子而言，球体仅变形一个波长的百分之一就基本消除了超窄MDR，而需要显著更大的非球形度才能抑制更宽的共振特征。当粒子形状与完美球体的偏差增大时，MDR的位置和轮廓也会受到影响。对于被平面切割的球体，超窄MDR对非球形度增加的抵抗力要强得多，并且其位置和轮廓不会改变。这些发现与被广泛接受的洛伦兹 - 米氏MDR物理解释一致。
