Optically adjustable light filaments generated by a compact laser convertor.

In the paper, the geometrical parameters and energetics of the extremely narrow pseudo-nondiffracting beams with the spot size of several micrometers are examined. The main attention is focused on design, realization and testing of the set-up enabling conversion of the laser diode beam or the fiber mode to the narrow Bessel-Gauss beam whose spot can be continuously relocated across the plane perpendicular to the beam propagation direction. Application of the laser convertor to the optical manipulation is demonstrated on experiments enabling transport of microparticles along a desired trajectory.