Modelling diffraction by facetted particles

A method to approximate azimuthally resolved light scattering patterns and phase functions due to diffraction and external reflection by strongly absorbing facetted particles is demonstrated for a cube and compared with results from an exact method, T-matrix. A phase function averaged over a range of orientations of a strongly absorbing hexagonal column of aspect ratio unity has been calculated and tested against Discrete Dipole Approximation (DDA) results for a size parameter of 50.

► Improved model of diffraction by faceted particle compared to projected cross sect. ► Kirchhoff approximation applied to sets of apertures corresponding to facets. ► The method has been tested against T-matrix results for a strongly absorbing cube. ► Method suitable for modelling external diffraction within geometric optics.