Siegman [Opt. Lett. 18, 675 (1993)] showed that binary-phase plates cannot improve laser beam quality. We demonstrate that continuous spiral phase elements can improve the quality of beams that originate from a laser operating with a pure high-order transverse mode. A theoretical analysis is presented, along with experimental results obtained with a CO<sub>2</sub> laser. The results reveal that a nearly optimal Gaussian output beam can be obtained with only a small decrease in the output power.
© 2000 Optical Society of America
(050.5080) Diffraction and gratings : Phase shift
(070.6110) Fourier optics and signal processing : Spatial filtering
(140.3300) Lasers and laser optics : Laser beam shaping
(140.3430) Lasers and laser optics : Laser theory
(140.3570) Lasers and laser optics : Lasers, single-mode
Ram Oron, Nir Davidson, Asher A. Friesem, and Erez Hasman, "Continuous-phase elements can improve laser beam quality," Opt. Lett. 25, 939-941 (2000)