Field-free molecular alignment control of filamentation

Abstract

Abstract:With an approach of controlling the nonlinearity of medium rather than the light field, the effect of field-free molecular alignment on filamentation and resulting white-light generation is studied. This is done by measuring the rotational wavepacket evolution of nitrogen molecules after passing of a femtosecond laser pump pulse by observing the nonlinear propagation dynamics of a variably delayed filament-producing probe pulse.

Control of laser-induced nonadiabatic molecular alignment in dissipative media

“…The standard version of the setup in Refs. [22,32], in which the pump and probe beams propagate collinearly and are discriminated spectrally rather than spatially, was used successfully for measurements at room temperature. Aside from easier adjustment, the setup has the additional advantage of providing a large interaction volume even for lenses with relatively short focal length.…”

Controlled formation of femtosecond laser-induced filaments in water

“…The critical power for self-focusing for an elliptical beam was found to be greater than a beam with cylindrical symmetry, and the role of the elliptical intensity distribution was discussed in details [14][15][16][17][18]. Studies also show that controlling and organizing filament formations are possible by inserting slits and meshes into the beam path of an intense laser pulse [19], creating Fresnel diffraction from a circular aperture [20], applying amplitude [21,22] and phase [23,24] modulation of the beam field, combining the phase plates [25], producing high order Hermite Gaussian beams [26] and Bessel Gaussian beams [27], probing nonlinear molecular alignment [28][29][30] and crossing two femtosecond laser beams [31] etc.…”