Three-dimensional optical transfer of rotating beams.

Systems in which the point spread function (PSF) is a rotating beam have increasing use in three-dimensional (3D) microscopy and depth estimation. We analyze in several ways the 3D optical transfer function (OTF) of Gauss Laguerre modes and rotating beams. This is based on analysis of 3D OTFs of general aperture functions. Consequently, we suggest a criterion for depth resolution based on an effective cutoff of the axial frequency response. This criterion can be used to optimize PSFs explicitly and directly, to maximize axial resolution.