Spectral and angular light-scattering from silica fractal aggregates

This work applies a new model based on the discrete dipole approximation to simulate the scattering of coherent broadband light from fixed and randomly oriented silica fractal aggregates. Two classes of aggregate morphology are considered; the standard aggregate with a single fractal dimension and superaggregates with two dimensions, both of which are generated from a Diffusion-Limited Cluster-Aggregation model. Light scattering from these aggregates is simulated over the short wave infrared to ultraviolet spectral range. We find features in the distribution of the spectral and angular scattered-intensities that do not disappear after orientation averaging and are seen for both types of aggregates. The important role played by the wavelength in q-space analysis is observed and we report the utility of a spectral q-space analysis for multi-dimensional objects like superaggregates with spectrally dependent refractive index.

► A new model based on the DDA to simulate the scattering of coherent broadband light. ► Spectral and angular light scattering for silica fractal aggregates. ► Distinctive scattering fingerprint for standard and hybrid fractal aggregates. ► Features in the scattered-intensities do not disappear after orientation averaging. ► Investigation of the role played by the wavelength in q-space analysis.