Author(s)

Wenting Wang^*, Jiayi Wang, Yide Zhang

College of Science, University of Shanghai for Science and Technology, Shanghai, China.

The droplet size, size distribution, refractive index, and temperature can be measured simultaneously by the rainbow technique. In the present work, the rainbow scattering diagram for a spherical droplet in the secondary rainbow region is simulated by the use of the generalized Lorenz-Mie theory. For achieving high spatial resolution in denser droplet sprays, a focused Gaussian beam is used. For droplet characterization, different inversion algorithms are investigated, which includes trough-trough (θ_min1 and θ_min2) method and inflection-inflection (θ_inf1 and θ_inf2) method. For the trough-trough algorithm, the absolute error of the refractive index is between −6.4 × 10⁻⁴ and 1.7 × 10⁻⁴, and the error of the droplet radius is only between −0.55% and 1.77%. For the inflection-inflection algorithm, the maximum absolute error of the inverted refractive index is less than −1.1 × 10⁻³. The error of the droplet radius is between −0.75% and 5.67%.

Particles Characterization, Rainbow Pattern, Generalized Lorenz-Mie Theory

Wang, W. , Wang, J. and Zhang, Y. (2021) Droplet Characterization Based on the Simulated Secondary Rainbows. Optics and Photonics Journal, 11, 133-139. doi: 10.4236/opj.2021.116011.