Geometric Scattering Regime

FIGURE 15.3 Extinction efficiency QCM for a water droplet (a) wavelength of the radiation is constant at X = 0.5 pm and diameter is varied (b) diameter = 2 pm and wavelength is varied (Bohren and Huffman 1983). 

This is twice as large as predicted by geometric optics, which is the so-called extinction paradox (Bohren and Huffman 1983). In qualitative terms, the incident wave is influenced 

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Particles for which a 1 fall into the so-called geometric scattering regime. In this case the scattering can be determined on the basis of the geometrical optics of reflection, refraction, and diffraction. Scattering is strongly dependent on particle shape and orientation... 

Figure 7-4 Different scattering modes for a spherical particle in the geometrical optics regime...

For very large particles, i.e. a 1 or Dp > 4-A., the laws of geometrical optics (also called the Fraunhofer regime) are applicable (van de Hulst 1981). The light scattering intensity varies approximately with the square of the particle diameter. 

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