We analyze a method for efficiently generating optical vortices by use of annular computer-generated holograms and a spatial light modulator. We found that there exists an optimal annular width by which the reconstructed vortex ring in the focal plane has the steepest gradient and the worthless subbright rings can be largely suppressed. We fitted a general formula for determining the value of this optimal annular width and propose a method for designing a multiring structure of optical vortices and specialized interferometric vortex patterns. Finally, we discuss the situation of a Gaussian beam as illuminated light and find that there exists an optimal beam waist that results in the best energy efficiency.
© 2005 Optical Society of America
(050.1970) Diffraction and gratings : Diffractive optics
(090.1760) Holography : Computer holography
(140.3300) Lasers and laser optics : Laser beam shaping
(140.7010) Lasers and laser optics : Laser trapping
(230.6120) Optical devices : Spatial light modulators
Cheng-Shan Guo, Xuan Liu, Xiu-Yun Ren, and Hui-Tian Wang, "Optimal annular computer-generated holograms for the generation of optical vortices," J. Opt. Soc. Am. A 22, 385-390 (2005)