title: Sidelobe reduction of tightly focused radially higher-order Laguerre-Gaussian beams using annular masks.
abstract: 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.
authors.affiliation: Hamamatsu Photonics K K, Central Research Laboratory, Hirakuchi, Hamakita-Ku, Hamamatsu 434-8601, Japan. ohtake@crl.hpk.co.jp
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ohtake
authors.forename: Taro
authors.initials: T
authors.lastname: Ando
authors.forename: Takashi
authors.initials: T
authors.lastname: Inoue
authors.forename: Naoya
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Haruyoshi
authors.initials: H
authors.lastname: Toyoda