Control of filamentation induced by femtosecond laser pulses propagating in air

Abstract

Filamentation formed by self-focusing of intense laser pulses propagating in air is investigated. It is found that the position of filamentation can be controlled continuously by changing the laser power and divergence angle of the laser beam. An analytical model for the process is given.

Femtosecond filamentation in transparent media

“…A control of the beginning of filamentation induced by femtosecond laser pulses has been achieved in experiments by Jin et al (2005) who showed that a change of both the laser energy and the beam divergence angle (via a deformable mirror) leads to a precise control of the beginning of filamentation. Liu et al (2006e) used a telescope so as to enlarge both the input beam diameter and the size of the beam inhomogeneities.…”

Taming the Collapse of Optical Fields

“…A great challenge and expectation is to tame the randomicity and then to realize the controllable and even designable filamentation. For this purpose, several methods have been proposed such as, controlling the input power and divergence angle19, shaping the field profile2021, using amplitude/phase mask22232425, and introducing spatial regularization26.…”

Filament-based stimulated Raman spectroscopy

“…The formation distance of the filament and the filament length (as characterized by the fluorescence emission in the plasma channel) from the laser can be controlled optically by manipulating the initial pulse chirp using pulse-shaping techniques 18,19 . Finally, filament formation can be controlled using deformable mirrors 20 .…”