Extreme Nonlinear Optics in the Atmosphere
Listen now
Description
Multiterawatt femtosecond duration laser pulses, when launched in the atmosphere, undergo extreme self-focusing to produce dramatic spectral superbroadening and breakdown the molecular constituents of air to produce extended electron-ion plasma channels. The dramatic nonlinear events occurring in the interaction zone while only qualitatively understood, have prompted a flurry of activity over the past decade into exploiting these phenomena in real-life applications. Some applications include femtosecond atmospheric lidar, remote detection of pollutants and/or chem/bio agents, remote laser induced breakdown spectroscopy (LIBS), control of lightning and remote terahertz spectroscopy. The University of Arizona is the lead institution in a new Multi-disciplinary University Research Initiative (MURI) project along with five other institutions. The goal is to gain a deeper understanding of the complex nonlinear physics involved and build mathematically rigorous and computationally feasible models of intense pulse filamentation in air and condensed media. In this talk, I will present a brief history of the development of this emerging field of nonlinear science, point to some successes achieved along the way and outline the strategy of the MURI team aimed at solving remaining outstanding problems. The Arizona team has been to the forefront in developing the present theoretical foundation and more recently we have built a TW femtosecond laser laboratory to support the theory and simulation effort. One intriguing departure from the status quo is to envisage laser beam profiles constituted from linear superpositions of conical waves. Such beams (Bessel and Airy) are remarkably robust under propagation and exhibit a self-healing property which is fundamentally different behavior from that of conventional Gaussian beams.
More Episodes
Abstract: The physical limit for the number of pixels per color channel per frame in an optical imager is approximately equal to the aperture area in square microns. While this limit is essentially achieved in megapixel scale cell phone cameras, the limit of 100 megapixels for cm apertures, 10...
Published 10/18/12
Abstract: The fate of an ultrashort laser pulse propagating in air depends crucially upon its peak power. Below a critical value, Pcr, group velocity dispersion and beam diffraction combine to rapidly reduce the pulse intensity. On the other hand, if P is less than Pcr, a completely different...
Published 10/18/12
Abstract: Organic semiconductor materials offer the potential of low-cost and flexible displays and lighting solutions, some of which have already made it to the marketplace. Despite this, much of the underlying optical physics remains poorly understood and hinders progress towards better and...
Published 10/18/12