Kerker M
Appl Opt. 1979 Apr 15;18(8):1180-9. doi: 10.1364/AO.18.001180.
This is a numerical study of electromagnetic scattering by particles exhibiting negative absorption, i.e., with refractive index m = n(1 + kappai), where the time dependence is exp(+iomegat). The particle is a homogeneous circular cylinder. The stimulating incident plane wave travels perpendicularly to the cylinder axis. The scattering, amplification, and extinction cross sections as well as the differential scattering cross sections were evaluated for n = 1.50 over the nkappa = 0.001-1 range for the size parameter up to alpha = 50, where alpha = 2pia/lambda (a is the radius and lambda is the wavelength). In some cases results were obtained for much larger values of alpha. The most remarkable finding was the occurrence of sharp resonances. Not only does this provide for large amplification of the scattered radiation traveling outward as spherical waves (for 3-D objects) or as cylindrical waves (for 2-D objects), but, because of the occurrence of negative extinction cross sections, it may also result in amplification of the incident plane wave. The present formalism (Lorenz-Mie for spheres; Rayleigh for cylinders) implies a particular and highly contrived mechanism for pumping and stimulation. However, the formalism may be extended to other particular mechanisms.
这是一项关于具有负吸收特性的粒子电磁散射的数值研究，即折射率(m = n(1 + \kappa i))，其中时间依赖关系为(\exp(+i\omega t))。粒子为均匀圆柱体。激发的入射平面波垂直于圆柱轴传播。对于尺寸参数(\alpha)高达(50)（其中(\alpha = 2\pi a / \lambda)，(a)为半径，(\lambda)为波长），在(n = 1.50)且(n\kappa = 0.001 - 1)的范围内评估了散射、放大和消光截面以及微分散射截面。在某些情况下，还获得了(\alpha)值大得多的结果。最显著的发现是出现了尖锐的共振。这不仅使得作为球面波（对于三维物体）或柱面波（对于二维物体）向外传播的散射辐射得到大幅放大，而且由于出现了负消光截面，还可能导致入射平面波的放大。目前的形式体系（球体用洛伦兹 - 米氏理论；圆柱体用瑞利理论）意味着一种特殊且高度人为设计的泵浦和激发机制。然而，该形式体系可扩展到其他特定机制。
