Red

Figure 4. The dependence of intensity and polarization on scattering angle when averaged excluding specular reflection produced at tilt angle of 90 degrees. Solid and dashed lines represent red and blue wavebands, respectively.

reduced in two wavelength intervals, 2.7-3 mm and 3.5-4 mm corresponding to blue and red in the visual. The fine structure in the plots is likely due to the finite number of orientations used in the averaging. The main trends are that the scattered light in the blue waveband has a higher intensity than in the red, thus indicating blue color, and for scattering angles smaller than 90 degrees the Polarimetrie color is blue, i.e. the polarization is greater in the blue waveband than in the red. This is interesting as blue color is often an indication of very small particles, which usually have red polarimetric color. This may make flakes distinguishable from other common particle shapes.

Figure 4 shows the intensity and polarization excluding the most dominant set of orientations, the average over rotation when the tilt angle is 90 degrees. The scattering is much different from the case simulating average over random orientation. The intensity is of course much lower but the color is still blue, and the polarimetric color at smaller scattering angles has changed to red. This illustrates, that randomly orientated flakes and flakes that are aligned in some preferred orientation(s), might be distinguishable based on their very different scattering properties.

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