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Proceedings Paper

Diffractive focusing of wide-aperture beams: theory and experiment
Author(s): Renat R. Letfullin; Oleg A. Zayakin; Thomas F. George
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Paper Abstract

It is shown theoretically and experimentally that when a Gaussian beam illuminates a bicomponent diffraction system with small Fresnel numbers, consisting of two plane screens with circular apertures on given optical axes, in a near zone of the second screen the effect of diffractive multifocal focusing of radiation is observed. In this case, the diffraction picture from the second screen in the focal planes represents the circular nonlocal bands of the Fresnel zones with a bright narrow peak at the center, whose intensity can exceed by six times the value of the incident wave intensity. The proposed diffractive method allows the focusing of the wide-aperture beams without using classical refraction elements such as lenses and prisms, and it is applicable to both low-intensive and high-power radiation. The energy efficiency of diffractive focusing of Gaussian beams is as high as 70%. Such a method can improve the energy efficiency of the fiber coupling of diode lasers and can increase the intensity of radiation on a fiber exit up to a factor of ten.

Paper Details

Date Published: 24 April 2001
PDF: 9 pages
Proc. SPIE 4270, Laser Resonators IV, (24 April 2001); doi: 10.1117/12.424669
Show Author Affiliations
Renat R. Letfullin, P.N. Lebedev Physical Institute (Russia)
Oleg A. Zayakin, P.N. Lebedev Physical Institute (Russia)
Thomas F. George, Univ. of Wisconsin/Stevens Point (United States)

Published in SPIE Proceedings Vol. 4270:
Laser Resonators IV
Alexis V. Kudryashov; Alan H. Paxton, Editor(s)

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