Khaled E E, Hill S C, Barber P W
Appl Opt. 1994 May 20;33(15):3308-14. doi: 10.1364/AO.33.003308.
The intensity of light scattered by a coated sphere illuminated with an off-axis Gaussian beam is calculated. Results are shown for different beam positions with respect to the sphere. As the beam is shifted further away from the surface of the sphere, the higher-Q morphology-dependent resonances become increasingly important in the backscatter spectra, and the angular scattering intensity becomes smoother.
The scattered intensity depends on the beam position, the refractive indices of the core and coat, the radius of the core, and the thickness of the coat. As the beam is moved further away from the sphere, the effect of the core on the scattering intensity decreases. When the incident Gaussian beam is focused outside of a particle with a relatively small core, the scattering spectra and angular scattering patterns become similar to those of a homogeneous sphere having the refractive index of the coat. These calculated results suggest that measurements of spectral scattering and angular scattering patterns for several Gaussian beam positions could be useful for the characterization of coated spheres.
计算了用离轴高斯光束照射的包覆球体散射光的强度。给出了光束相对于球体处于不同位置时的结果。随着光束进一步远离球体表面，在背向散射光谱中，较高品质因数的形态相关共振变得越来越重要，并且角散射强度变得更加平滑。
散射强度取决于光束位置、芯层和包覆层的折射率、芯层半径以及包覆层厚度。随着光束进一步远离球体，芯层对散射强度的影响减小。当入射高斯光束聚焦在具有相对较小芯层的粒子外部时，散射光谱和角散射图案变得类似于具有包覆层折射率的均匀球体的散射光谱和角散射图案。这些计算结果表明，测量几个高斯光束位置的光谱散射和角散射图案可能有助于表征包覆球体。
