  Bessel beams are known for their property of maintaining
propagation-invariant transverse intensity distribution. The true Bessel beams
has unlimited energy, however the experimental realization of limited energy
Bessel-like beams provides almost diffraction-free beams over a certain
distance. These beams are applicable to microfabrication, particle manipulation
etc. where long and narrow intense beam is needed. A type of laser beams that
maintains narrow intensity peak for long distances are often called optical
needles. In this paper we propose a construction of an optical needle using a
superposition of vector Bessel beams and for flexible engineering of axial
intensity profile. We investigate both theoretically and experimentally
generation of various optical beams of different axial profiles, lengths, beam
widths etc. We use a spatial light modulator as a toy model of an optical
element to shape the spatial spectrum of the beam. Moreover, we demonstrate
distortions introduced into the optical needle by a planar interface between
two dielectric media: spherical aberration and astigmatism due to the nonzero
inclination angle and discuss ways to correct them.
