The 6^th International Conference on Graphene and Novel Nanomaterials
(GNN 2024)

Abstract: In a depolarized dynamic light scattering setup, particles undergoing Brownian motion scatter the light toward a photodetector with two polarization geometries: vertical-vertical (VV) and vertical-horizontal (VH). If the particles are nanorods (i.e., they have a cylindrical shape described by a diameter and a length), an analysis of the fluctuations of the light recorded in the VV and VH geometries permits information to be retrieved about the translational and rotational diffusion of the particles, thus allowing their mean diameter and length to be estimated. In this study, we estimate the mean diameter, the mean length, the variance of the diameters, and the variance of the lengths of nanorods using a generalized regression neural network (GRNN). To train the GRNN, training samples are randomly generated around an initial guess estimated using a Tikhonov regularization. The predictors of the GRNN are the normalized electric field autocorrelation functions of the scattered light recorded by the photodetector at multiple scattering angles. The translational and rotational diffusion coefficients of a nanorod are described using the bead-shell model. In the present work, the bivariate probability density function (PDF) of the diameters and lengths is Gaussian and unimodal. The possibility of extending this approach to estimate other characteristic information about a multimodal PDF will be also discussed.

Biography: He obtained his PhD from the INSA school in Rouen, France, in 2012. His research work, conducted at the CORIA laboratory under the supervision of Prof. Gerard Grehan, involved estimating characteristic information such as the size, 3D positions and refractive index of a group of spherical particles illuminated by a plane wave, which scatter the light toward a camera. This work caused him to become interested in the Lorenz-Mie theory (LMT), which describes the interaction between a plane wave and a spherical particle. This in turn sparked his interest in how the LMT has been extended to the generalized Lorenz-Mie theory (GLMT), which describes the interactions between arbitrarily shaped beams and particles of regular shape (for instance aggregated spherical particles, spheroidal particles, particles with inclusion, and so on).
After two years of postdoctoral studies at Xidian University (2013–2015), he undertook postdoctoral studies at the University of Shanghai for Science and Technology (USST) under the supervision of Prof. Xiaoshu Cai (2016–2018). While at USST, he became interested in the field of optical metrology of nanoparticles.
Since 2018, when he returned to Xidian University to work with Prof. Yiping Han and Prof. Jiajie Wang, his main interests have involved the descriptions of light scattering by regular particles in the framework of the GLMT and the optical metrology of particles. His lectures at Xidian University focus on university physics, optical metrology, and light scattering by small particles.