Atsushi WADA, Hiroyuki OHMINATO, Takashi YONEMURA, Yoko MIYAMOTO and Mitsuo TAKEDA

Department of Information and Communication Engineering, The University of Electro-Communications, Tokyo 182-8585, Japan

(Received August 12, 2005; Accepted August 25, 2005)

Seidel comatic aberration is an important cause of deformation for a Laguerre–Gaussian (LG) beam. In addition, mono-axial comatic aberration, whose phase modulation depends only on one transverse coordinate, is also an important cause of beam deformation. Deformation of an LG beam by such aberrations is analyzed through numerical simulation based on the angular spectrum method. It is also shown that for holographically generated LG beams quadratic spatial variation of grating pitch can produce seidel and mono-axial comatic aberrations. An example of an experimentally generated LG beam with mono-axial comatic aberration is reported.

Key words: Laguerre–Gaussian beam, phase singularity, optical design and fabrication, computer hologram, diffraction, aberration