Gautam Laboratory for Advanced Aerosol Dynamics
and Light Scattering Research 

Dr. Gautam is engaged in research combining experimental and theoretical aspects of electromagnetic and light scattering, particularly in atmospheric, climate, and colloid physics.  His work involves designing and developing an angularly resolved, multi-angle light scattering setup for real-time, in situ characterization of the optical properties of aerosol particles, along with their identification and tracking. Optical properties include phase function, extinction (scattering + absorption), asymmetry parameter, albedo, lidar ratio, linear depolarization ratio (LDR), and other scattering matrix elements. His recent research has been particularly focused on the development of several key instruments and concepts: 1) a cost-effective sensor for monitoring ambient particulate matter using near-forward scattering, 2) a polar nephelometer capable of measuring light scattering from an extreme forward scattering angle to near exact backscattering angle, 3) theoretical and experimental analysis of the sensitivity of key backscattering phenomena in relation to particle microphysical properties such as size/size distribution, shape, and complex refractive index, 4) the optical properties of soot in various stages of aging, including soot coated with sulfate and other organic materials; and 5) optimizing current aerosol measurement technologies, such as integrating nephelometers by incorporating novel optical schemes. 

Before joining DRI, Dr. Gautam was a PhD student at the Department of Physics, Kansas State University, where he designed and built an angularly resolved multi-angle light scattering setup capable of measuring scattered light from extreme forward angles (0.32°) to backscatter (178.6°), using an innovative optical design. He used this system to study the optical properties of aerosol particles with diverse sizes, shapes, and complex refractive indices. Additionally, Dr. Gautam explored the correlation between light scattering-derived particle sizes and those measured by commercial aerosol instruments, such as an Aerodynamic Particle Sizer (APS). His research also involved microphysical characterization of aerosol particles through techniques including transmission/scanning electron microscopy (TEM/SEM), X-ray diffraction (XRD), and Ultra-Small Angle X-ray Scattering (USAXS). He has developed extensive expertise in laser systems, optics, holography technique, and characterizaing particles from sub- to super-micron scales. 

Contact: Prakash.Gautam@www-dev.dri.edu  or (1)785-317-7470