[Seminar] Non-resonant, non-intrusive, seed-less, single shot and simultaneous temperature, density and flow velocity gas flow characterization with coherent Rayleigh-Brillouin scattering

Metrology is a founding pillar and a driving force of scientific discovery and understanding. Albeit its key importance in all aspects of science and engineering, the field is still dominated by the use of mechanical, intrusive probes for flow velocity and pressure measurements. To tackle the matter, which is of key importance to the development of a plethora of science and engineering fields, our group is developing single shot coherent Rayleigh-Brillouin scattering (CRBS) as an alternative, non-intrusive probe for neutral and plasma flow thermodynamic characterization.
CRBS is a four-wave mixing diagnostic technique that relies on the creation of an optical lattice in a medium due to the interaction between polarizable particles and intense laser fields. Single shot CRBS1 has been demonstrated to be the coherent analog of spontaneous Rayleigh-Brillouin scattering in measuring the temperature, pressure, bulk and shear viscosity, speed of sound and polarizability of a gas or gas mixture2, as well as nanoparticles produced in an arc discharge3.In this talk, an overview on the theory and experimental aspects of single shot CRBS will be presented along with our recent work in measuring simultaneously the temperature, density (and thus the pressure) and flow velocity4 of neutral species radially across a neutral gas flow and a glow discharge. Finally, the feasibility and working progress towards the use of CRBS as a thermodynamic characterization technique for partially/fully ionized gases as well as of liquid flows will be discussed.

Alexandros Gerakis is a Senior Research & Technology Associate at the Luxembourg Institute of Science & Technology (LIST) and a 2021 FNR ATTRACT Fellow. He obtained his BSc from the School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Greece and his Master’s degree from St Andrews and Herriot-Watt Universities, in “Photonic and Optoelectronic Devices”. He holds a PhD in Physics from University College London. Prior to joining LIST, he was a postdoc at Harvard University, was an Associate Research Physicist at the Princeton Plasma Physics Laboratory and an Assistant Professor at the Aerospace Engineering Department, Texas A&M University, leading the “Optical Probing & Manipulation” Group.

(All are welcome to attend.)