Extension of filament propagation in water with Bessel-Gaussian beams

Abstract

We experimentally studied intense femtosecond pulse filamentation and propagation in water for Bessel-Gaussian beams with different numbers of radial modal lobes. The transverse modes of the incident Bessel-Gaussian beam were created from a Gaussian beam of a Ti:sapphire laser system by using computer generated hologram techniques. We found that filament propagation length increased with increasing number of lobes under the conditions of the same peak intensity, pulse duration, and the size of the central peak of the incident beam, suggesting that the radial modal lobes may serve as an energy reservoir for the filaments formed by the central intensity peak.

Free-Space Nonlinear Beam Combining for High Intensity Projection

“…Nearly two decades of experimental and theoretical studies of filamentation in air with near-infrared femtosecond laser pulses, have elucidated the principal physical processes involved 15 – 20 . Most studies have been performed with laser powers sufficient for the eventual formation of a filament, in air stabilized by partial ionization and the consequential impact of the liberated electrons on the beam propagation.…”

Field-free molecular alignment control of filamentation

“…An intense femtosecond pulse filamentation and propagation were experimentally studied in water for Bessel-Gaussian beams with different numbers of radial modal lobes . [21]. The filament propagation length increased with increasing number of lobes under the conditions of the same peak intensity, pulse duration, and the size of the central peak of the incident beam, suggesting that the radial modal lobes feed energy to the filaments formed by the central intensity peak.…”

“…There are several possibilities investigated to control the spatial and temporal characteristics of the filamentation process and resulting white-light generation [11,[18][19][20][21]. By changing the transverse spatial phase of an initial Gaussian beam with a computer-generated hologram technique and a spatial light modulator [11] beams with phase discontinuities and steeper intensity gradients were created.…”

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.…”