Debye Series of Scattering by a Multi-Layered Cylinder in an Off-Axis 2D Gaussian Beam

The Debye series of light scattering by an infinite multi-layered cylinder in an off-axis 2D Gaussian beam is studied. A simplified but rigorous iterative formula for scattering coefficients is presented. The numerical calculations of
scattering intensity by a cylinder in on-axis and off-axis beams are developed. It is indicated that the results of Debye series reach an agreement with those of generalized Lorenz--Mie theory and the off-axis distances vary the results to a great extent. The Debye series components of a two-layered cylinder are further discussed. The relations between them with rainbow phenomena are analysed.