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Controlling femtosecond filament propagation using externally driven gas motion



Jared K. Wahlstrand, Nihal Jhajj, H M. Milchberg


The thermal density depression (or “density hole”) produced by a high repetition rate femtosecond filament in air acts as a negative lens, altering the propagation of the filament. We discuss the effects of externally driven gas motion on these density holes and the resulting filament deflection, and we derive an expression for the gas velocity that maximizes the effect. At gas velocities more than 3 times this value, the density hole is displaced from the filament and no longer affects filament propagation. We demonstrate density hole displacement using an audio speaker-driven sound wave, leading to a controllable, repeatable deflection of the filament. Applications are discussed, including quasi phase matching in gas-based nonlinear optics.
Optics Letters


nonlinear optics, thermal effects, acoustics


Wahlstrand, J. , Jhajj, N. and Milchberg, H. (2019), Controlling femtosecond filament propagation using externally driven gas motion, Optics Letters, [online], (Accessed May 29, 2024)


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Created January 2, 2019, Updated February 7, 2019