We report the reduction of sidelobes in tight focusing patterns of radially higher-order Laguerre–Gaussian (LG) beams with nonhelical phase structures. Numerical calculations based on the vectorial Debye theory reveal that a class of annular masks reduces sidelobes in the tight focusing patterns only for radially even-order LG beams. The present scheme produces small focal spots beyond the diffraction limit suitable for application to scanning microscopy, laser fine processing, etc.
© 2008 Optical Society of America
Original Manuscript: October 5, 2007
Revised Manuscript: December 18, 2007
Manuscript Accepted: February 14, 2008
Published: March 14, 2008
Vol. 3, Iss. 4 Virtual Journal for Biomedical Optics
Yoshiyuki Ohtake, Taro Ando, Takashi Inoue, Naoya Matsumoto, and Haruyoshi Toyoda, "Sidelobe reduction of tightly focused radially higher-order Laguerre-Gaussian beams using annular masks," Opt. Lett. 33, 617-619 (2008)