Bessel beam parameter optimization with adjustable aberrator

Abstract

Transformation of ordinary laser beams of Gaussian type into the ones of Bessel type gives a number of advantages. In particular, it may improve a multi-mode beam energy distribution in the far zone and keep it stable over a long range of propagation distances. A usual method of the Bessel beam formation is based on the use of one or a pair of axicons, at that the latter is used for creating annular beams with small conic angles optimized for long range propagation. The disadvantage of axicons is their fixed geometry not allowing the beam parameter adjustment. An additional Bessel beam improvement allowing to reach a finer energy distribution comes from injection into it a controllable amount of spherical aberration. This requires development of a specialized optical system, which adds adjustable spherical aberration to the laser beam. Efficient design of such an optical system has been created and experimentally tested on the transformation of a multi-mode laser beam into Bessel beam.