Abstract

The electromagnetic fields scattered when a plane wave is incident on an oblate spheroid in the side-on orientation may be calculated using a generalization of Mie theory, and the results may be decomposed in a Debye series expansion. A number of optical caustics are observed in the computed scattered intensity for the one internal reflection portion of the Debye series for scattering angles in the vicinity of the first-order rainbow, and are analyzed in terms of the rainbow, transverse cusp, and hyperbolic umbilic caustics of catastrophe optics. The specific features of these three caustics are described, as is their assembly into the global structure of the observed caustics for spheroid scattering. It is found that, for a spheroid whose radius is an order of magnitude larger than the wavelength of the incident light, the interference structure accompanying the transverse cusp and hyperbolic umbilic caustics is only partially formed.

© 2010 Optical Society of America

Simulation of optical caustics associated with the tertiary rainbow of oblate droplets

Lulu Guan, Haitao Yu, Jianqi Shen, and Cameron Tropea
Appl. Opt. 55(23) 6447-6451 (2016)

Opening rate of the transverse cusp diffraction catastrophe in light scattered by oblate spheroidal drops

Cleon E. Dean and Philip L. Marston
Appl. Opt. 30(24) 3443-3451 (1991)

Debye series for light scattering by a spheroid

Feng Xu, James A. Lock, and Cameron Tropea
J. Opt. Soc. Am. A 27(4) 671-686 (2010)

Scattering of white light from levitated oblate water drops near rainbows and other diffraction catastrophes

Harry J. Simpson and Philip L. Marston
Appl. Opt. 30(24) 3468-3473 (1991)

Simulation of the optical caustics associated with the primary rainbow for oblate spheroidal drops illuminated by a Gaussian beam

Jiayi Wang, Haitao Yu, Jianqi Shen, Bin Yang, and Cameron Tropea
Opt. Express 29(1) 377-384 (2021)