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Title: Generation of low-divergence laser beams

Abstract

Apparatus for transforming a conventional beam of coherent light, having a Gaussian energy distribution and relatively high divergence, into a beam in which the energy distribution approximates a single, non-zero-order Bessel function and which therefore has much lower divergence. The apparatus comprises a zone plate having transmitting and reflecting zones defined by the pattern of light interference produced by the combination of a beam of coherent light with a Gaussian energy distribution and one having such a Bessel distribution. The interference pattern between the two beams is a concentric array of multiple annuli, and is preferably recorded as a hologram. The hologram is then used to form the transmitting and reflecting zones by photo-etching portions of a reflecting layer deposited on a plate made of a transmitting material. A Bessel beam, containing approximately 50% of the energy of the incident beam, is produced by passing a Gaussian beam through such a Bessel zone plate. The reflected beam, also containing approximately 50% of the incident beam energy and having a Bessel energy distribution, can be redirected in the same direction and parallel to the transmitted beam. Alternatively, a filter similar to the Bessel zone plate can be placed within the resonatormore » cavity of a conventional laser system having a front mirror and a rear mirror, preferably axially aligned with the mirrors and just inside the front mirror to generate Bessel energy distribution light beams at the laser source. 11 figures.« less

Inventors:
Issue Date:
OSTI Identifier:
5435458
Patent Number(s):
5245619 A
Application Number:
PPN: US 7-817009
Assignee:
PTO; EDB-94-046757
DOE Contract Number:  
AC09-89SR18035
Resource Type:
Patent
Resource Relation:
Patent File Date: 3 Jan 1992
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; LASER RADIATION; BEAM OPTICS; BESSEL FUNCTIONS; COHERENT RADIATION; ENERGY SPECTRA; GAUSS FUNCTION; LASER CAVITIES; LASER MIRRORS; LIGHT TRANSMISSION; OPTICAL FILTERS; ELECTROMAGNETIC RADIATION; FILTERS; FUNCTIONS; MIRRORS; RADIATIONS; SPECTRA; 426002* - Engineering- Lasers & Masers- (1990-)

Citation Formats

Kronberg, J W. Generation of low-divergence laser beams. United States: N. p., 1993. Web.
Kronberg, J W. Generation of low-divergence laser beams. United States.
Kronberg, J W. Tue . "Generation of low-divergence laser beams". United States.
@article{osti_5435458,
title = {Generation of low-divergence laser beams},
author = {Kronberg, J W},
abstractNote = {Apparatus for transforming a conventional beam of coherent light, having a Gaussian energy distribution and relatively high divergence, into a beam in which the energy distribution approximates a single, non-zero-order Bessel function and which therefore has much lower divergence. The apparatus comprises a zone plate having transmitting and reflecting zones defined by the pattern of light interference produced by the combination of a beam of coherent light with a Gaussian energy distribution and one having such a Bessel distribution. The interference pattern between the two beams is a concentric array of multiple annuli, and is preferably recorded as a hologram. The hologram is then used to form the transmitting and reflecting zones by photo-etching portions of a reflecting layer deposited on a plate made of a transmitting material. A Bessel beam, containing approximately 50% of the energy of the incident beam, is produced by passing a Gaussian beam through such a Bessel zone plate. The reflected beam, also containing approximately 50% of the incident beam energy and having a Bessel energy distribution, can be redirected in the same direction and parallel to the transmitted beam. Alternatively, a filter similar to the Bessel zone plate can be placed within the resonator cavity of a conventional laser system having a front mirror and a rear mirror, preferably axially aligned with the mirrors and just inside the front mirror to generate Bessel energy distribution light beams at the laser source. 11 figures.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1993},
month = {9}
}