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Nonlinear confinement of multi-teraWatt ultrashort laser pulses over Kilometer ranges

Sonderseminar

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Abstract:

We have identified a major paradigm shift relative to near-IR filamentation when high power multiple terawatt laser pulses are propagated at mid-IR and long-IR wavelengths within key atmospheric transmission windows. Individual filaments at near-IR (800nm) wavelengths typically persist only over tens of centimeters, despite the whole beam supporting them being sustained over about a Rayleigh range.  In the important mid-IR atmospheric window (3.2-4 µm) optical carrier wave self-steepening (carrier shocks) tend to dominate and modify the onset of long range filaments. These shocks generate bursts of higher harmonic dispersive waves that constrain the intensity growth of a filament to well below the traditional ionization limit, making long range low loss propagation possible. For long wave pulses in the 8-12 µm atmospheric transmission window, many electron dephasing collisions from separate gas species acts to dynamically suppress the traditional Kerr self-focusing lens action and leads to a new type of whole beam self-trapping over multiple Rayleigh ranges. This prediction is key as strong linear diffraction at these wavelengths is a major problem and normally requires large launch beam apertures.

I will review our continuing work in this area and will also discuss some recent efforts to develop MWIR and LWIR high power pulsed sources.