Kuanfang REN is a Guest Professor at the International Research Center for Carbon Neutralization, Hangzhou International Innovation Institute of Beihang University. He graduated from the Department of Physics, Shaanxi Normal University in February 1982, received an M.Sc. in Radio Physics from Xidian University in February 1988, went to France under a government scholarship in 1990, and obtained a Ph.D. from the University of Rouen in 1995. From 1993 to 1998, he worked as a Contract Researcher at the CORIA Institute (UMR 6614, CNRS). In 1998, he was appointed Associate Professor at the University of Rouen, became a tenured Full Professor in France in 2008, and was promoted to First-Class Professor in 2015.

He has dedicated thirty-five years to teaching and research at CORIA (UMR 6614, CNRS), a joint institute of the University of Rouen, INSA Rouen, and CNRS. He has served as Vice-Chairman of the Expert Committee on Optics, Energy, and Processes at the University of Rouen, the founding chairman of the Federation of Associations of Chinese Scholars in France, and President of the Association of Chinese Scientists and Engineers in France. He has long been committed to fostering Sino-French cooperation and exchange in scientific research and education, promoting joint research, faculty and student exchanges, and dual-degree programs among multiple institutions. His teaching covers optics, mechanics, applied mathematics, and fluid measurement, with experience in both pre-university and university-level education, and with a deep understanding of the distinct French university system and the elite engineering education system.

Major Academic Contributions:

His research has long focused on light–particle interactions and novel fluid measurement techniques, yielding systematic innovations in three distinctive areas.

1.     Shaped Beam Scattering Theory: Since 1990, he has contributed to the Generalized Lorenz–Mie Theory (GLMT), increasing the computation speed of Gaussian beam coefficients by a factor of 100 to 500. He proposed the integral localized approximation and the plane wave expansion method, and was the first to apply GLMT to compute radiation pressure and torque on particles by shaped beams, leading to the development of ABSphere, a software for light/electromagnetic scattering.

2.     Optical Particle Measurement Techniques: For the inverse problem in extinction spectroscopy, he proposed a weighted correction scheme and developed fast, robust algorithms along with a portable measurement system, reducing data processing time from hours on supercomputers to minutes on personal computers, thus enabling real-time online measurement. These outcomes have been applied to wet steam, automotive emissions, and particulate measurements, with a 25-year continuous collaboration with Électricité de France (EDF) and support from the French National Research Agency (ANR) and the ITER project.

3.     Ray Theory of Waves: To address the bottleneck of fast and accurate computation of wave interactions with large irregular objects, he introduced the novel concept of regarding wavefront curvature as an intrinsic property of rays, derived the wavefront equation, and established the Vector Complex Ray Model (VCRM). By integrating this with physical optics and the uniform asymptotic theory, he developed the Ray Theory of Waves (RTW), providing a complete framework for studying wave scattering by non-spherical object and wave interaction with irregular surfaces. This model has been successfully applied to scattering calculations for spheroids, liquid jets, pendant drops, and raindrops, with experimental validations confirming its flexibility, speed, and accuracy, while also clarifying several long-standing questions regarding Airy theory since the 19th century. This research has received strong support from the French National Research Agency and other programs.

By 2025, he has supervised 12 doctoral students, published 117 papers in leading journals and 154 conference papers, developed six software packages, and led or participated in numerous European Community and French research projects.