Abstract

A model is proposed to compute the salient optical caustic partitions occurring in the primary rainbow for oblate spheroidal drops. By computing the boundary limits of outgoing rays, the optical caustic structures (termed rainbow and hyperbolic umbilic fringes) for tilted drops are calculated and compared with those for aligned (untilted) drops. The curvature of the rainbow fringe and the shifts of cusp caustics are discussed as well. The observed properties of the caustics can potentially be used for drop measurements. The model could also be applied to compute the optical caustics for drops with arbitrary shape, arbitrary orientation, and shaped beam illumination.

© 2019 Optical Society of America

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)

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

Haitao Yu, Feng Xu, and Cameron Tropea
Opt. Lett. 38(21) 4469-4472 (2013)

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)

Generalized rainbow patterns of oblate drops simulated by a ray model in three dimensions

Qingwei Duan, Fabrice R. A. Onofri, Xiang’e Han, and Kuan Fang Ren
Opt. Lett. 46(18) 4585-4588 (2021)

Optical caustics associated with the primary rainbow of oblate droplets: simulation and application in non-sphericity measurement

Haitao Yu, Feng Xu, and Cameron Tropea
Opt. Express 21(22) 25761-25771 (2013)