Engineering the axial intensity of Bessel beams

摘要

Bessel beams (BBs) appear immune to diffraction over finite propagationdistances due to the conical nature of light propagation along the opticalaxis. This offers promising advantages in laser fabrication. However, BBsexhibit a significant intensity variation along the direction of propagation.We present a simple technique to engineer the axial intensity of the BB overcentimeters-long propagation distances without expansion of the incoming laserbeam. This method uses two diffractive optical elements (DOEs), one convertsthe input Gaussian intensity profile to an intermediate intensity distribution,which illuminates the second DOE, a binary axicon. BBs of desired axialintensity distribution over few centimeters length can be fabricated.