Mathematical Modeling and Experimental Validation of Ultrafast Nonlinear Light-Matter Coupling associated with Filamentation in Transparent Media

Support: AFOSR FA9550-10-1-0561

The ability to control, propagate and generate intense light filaments at remote locations in the atmosphere with concomitant plasma strings and white-light continua provides exciting opportunities for the DOD across a broad landscape of applications. A subset of these applications include remote generation of a super-continuum for absorption monitoring of trace gases in the atmosphere, laser induced breakdown spectroscopy, filament formation for terahertz generation and for remotely establishing electrically conducting channels, localized EMP generation, low-divergence (below diffraction limit) beam propagation and remote guide-star beacons for adaptive optics.

The multidisciplinary university research initiative grant (AFOSR FA9550-10-1-0561) has the University of Arizona as the lead institution with five external universities as partners. The focus of the MURI project is to gain a fundamental understanding of all physical processes involved in the propagation of ultra-intense femtosecond laser pulses through the atmosphere with the aim of designing new forms of robust laser beams that can propagate over much longer distances than conventional beams. Applications of this novel atmospheric “light-string” are many and varied including: femtosecond atmospheric LIDAR and remote detection of pollutants, explosive, chem./bio agents; artificial guidestar for turbulence correction in astronomy, remote plasma generation for Laser Induced Breakdown Spectroscopy (LIBS) and redirection of lighting strikes.

The assembled MURI team, with the core mathematics effort housed at the Arizona Center for Mathematical Sciences (ACMS), University of Arizona, brings a unique mix of mathematics, theoretical physics and ultrafast experimental laser science expertise to tackle a truly grand challenge problem. External theory groups involving the University of Colorado and the University of Central Florida further augment a strong Arizona core. An in-house ACMS and external experimental teams at the JILA, University of Colorado, Cornell University, Temple University and the Colorado School of Mines provide the critical experimental validation backing for tests of theory/simulation results generated by the core mathematics/theory groups.

A central theme of our proposed research is a paradigm shift away from phenomenology and towards a rigorous mathematically and physically self-consistent foundation that will be the key enabler for development of critically important basic research breakthroughs in ultrafast laser propagation in gaseous and condensed media and future dual use technology applications. A major project investment is focused on training and education of young researchers. From the outset, we recognize severe shortcomings in our understanding of fundamental nonlinear processes associated with the propagation of intense ultrashort laser pulses in the above media. Our project breaks the problem down into 4 critical phases:

1. Initial pulse launch conditions - spatial beam and temporal pulse shaping and control,
2. Nonlinear interaction and ultrafast photoionization - plasma initiation,
3. Coupling of ultrashort pulses to established plasmas
4. Multiple filament interaction in propagating multi-Terawatt pulses.

The assembled MURI team consists of a core applied mathematics and theoretical physics (Moloney, Kolesik, Wright, Newell, Glasner, Brio, Venkataramani) and experimental femtosecond optics (Polynkin) at ACMS and external theoretical physicists Becker and Jaron-Becker at JILA, University of Colorado, Christodoulides (Central Florida) and experimentalists Murnane, Kapetyn (University of Colorado), Levis (Temple), Gaeta (Cornell) and Durfee (Colorado School of Mines).

The MURI team will maintain strong collaborative links with Air Force Research scientists (Roach at AFRL Kirtland and Albanese (Brooks City AFB). The MURI team will work in close collaboration with AFRL (Kirtland) to transition expertise, research personnel and discoveries to their AFRL TW laser facility for field tests.

MURI Participants

Jerome V. Moloney, Miroslav Kolesik, Moysey Brio	Andreas Becker and Agnieszka Anna Jaron-Becker	Alan Newell, Karl Glasner, Shankar Venkataramani
Charles Durfee and Jeff Squier		Alex Gaeta
Henry Kapetyn and Margaret Murnane	Robert J. Levis	Demetrios Christodoulides

School and Workshop 2012

The school is intended for graduate students or advanced undergraduate students, seeking an accelerated exposure to theory and mathematics describing ultrashort pulse propagation. The school is organized in conjunction with the Multidisciplinary University Research Initiative (MURI) Semi-annual Review, March 21 - March 22, 2011, and is hosted by Arizona Center for Mathematical Sciences which is located in the Meinel Optical Sciences Building at the University of Arizona.

This year's school will have a focus area of Ultrashort Physics of Light Matter Coupling. The main lecture topics will be:

• Intense Field Single and 2-electron Photo-Ionization of Atoms and Molecules
• Non-Equilibrium Plasma Theory: Many-Body Effects and Coupling to Light Field
• Building Physics Models for Ultra Short Pule (USP) Propagation

School Poster (PDF format)

Please click on the link below to view this year's Class Schedule:

School Schedule (PDF format)

School and Workshop 2011

Full length videos of last year's school presentations are available for online viewing here (password required)

• School opening address
• Basic elements from the theory of perturbations
• Universal equations describing nonlinear optical pulse propagation
• Computational Methods for Nonlinear PDEs describing Ultrashort Optical Pulse Propagation
• Dynamics of Ionization and Accompanying Processes in Intense Laser Fields
• Microscopic Theory of Plasma Formation: From the Wigner Function to Transport Equations
• Non-diffracting beams, conical waves and optical bullets
• Multielectron excitation of molecules by strong-field laser pulses and local spectrum broadening

Experimental facility supporting MURI

This lab is a dedicated facility that provides experimental support for the on-going theory/simulations program in extreme nonlinear optics at the Arizona Center for Mathematical Sciences. The lab facilities have been assembled under support from the Defense University Research Instrumentation Program (DURIP) by the US Air Force Office of Scientific Research. We are located in the Meinel Building of the College of Optical Sciences, on the University of Arizona campus in Tucson. The main focus of our experiments is femtosecond laser filamentation in gaseous media and related phenomena.

Further infomation on our experimental facilities is available here

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