Physical Chemistry Seminar: Spatiotemporal Dynamics and Universality in Laser-Induced Plasma

Abstract:

Laser-induced plasmas play a role in a wide range of applications, from defense and aerospace to pollutant detection and even lightning guidance. However, plasma formation is a highly nonlinear process, making its structure extremely sensitive to laser and focusing conditions. Understanding how these plasmas form and evolve remains a major challenge, particularly because many diagnostic techniques provide limited information about their internal spatial structure. Consequently, important aspects of how these plasmas form, reshape, and evolve remain hardly addressed.

In this seminar, I will present a method based on optical diffractometry that allows us to follow the plasma's density, size, and shape with high spatial and temporal resolution. Our measurements reveal a surprising behavior: despite very different formation histories, plasmas generated by different laser energies converge toward nearly identical profiles at a particular position beyond the laser focus. Time-resolved measurements also reveal distinct density-dependent relaxation and reshaping dynamics. We further introduce a simplified propagation model that explains this spatial convergence and reveals scaling laws that hold across different laser and focusing conditions.

Together, these findings uncover unexpected order in a highly nonlinear process, providing a general framework for understanding, comparing, and potentially controlling laser-induced plasmas.

Seminar Organizer: Dr. Anael Ben Asher