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Please use this identifier to cite or link to this item: http://hdl.handle.net/10204/6279

Title: Superresolution beams
Authors: Ngcobo, S
Ait-Ameur, K
Forbes, A
Keywords: Superresolution beams
Gaussian beams
Laguerre Gaussian beams
Diffractive optical element
Beam shaping
Issue Date: Nov-2011
Citation: Ngcobo, S, Ait-Ameur, K and Forbes, A. Superresolution beams. African Laser Centre Workshop, Cape Town, November 2011
Series/Report no.: Workflow;9672
Abstract: The transformation of a Gaussian beam (GB) into a symmetrical higher order TEMp0 Laguerre Gaussian beam (LGB) intensity distribution of which is further rectified and transformed into a Gaussian intensity distribution in the plane of a converging lens will produce a sharper focused beam which has transverse high resolution properties. The generated high resolution beam is very useful in improving the spatial resolution of optical imaging microscopes by making the central diffractive spot smaller than the Airy spot. The intracavity beam shaping of the GB is achieved by using an annular binary Diffractive Optical Element (DOE) whose geometry is in connection with the location of the Laguerre polynomial zeros. The DOE imposes positions of p zeros of intensity distributions on the GB, resulting to a generation of TEMp0 beams where there are minimum losses. The focused high resolution beams will then be achieved by shaping the generated higher order LG TEMp0 beams using a binary DOE which has annular zones capable of introducing a phase shift of zero or p on the alternately out of phase rings of the TEMp0 beams into a unified phase and then focusing the rectified beam to generate a high resolution beam which has a Gaussian beam intensity distribution at the focus.
Description: African Laser Centre Workshop, Cape Town, November 2011
URI: http://hdl.handle.net/10204/6279
Appears in Collections:Laser physics and technology
General science, engineering & technology

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