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Title: Diffractive optical elements for transformation of modes in lasers

Abstract

Spatial mode conversion modules are described, with the capability of efficiently transforming a given optical beam profile, at one plane in space into another well-defined optical beam profile at a different plane in space, whose detailed spatial features and symmetry properties can, in general, differ significantly. The modules are comprised of passive, high-efficiency, low-loss diffractive optical elements, combined with Fourier transform optics. Design rules are described that employ phase retrieval techniques and associated algorithms to determine the necessary profiles of the diffractive optical components. System augmentations are described that utilize real-time adaptive optical techniques for enhanced performance as well as power scaling.

Inventors:
; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1257998
Patent Number(s):
9,373,928
Application Number:
14/797,003
Assignee:
Lawrence Livermore National Security, LLC (Livermore, CA) LLNL
DOE Contract Number:
AC52-07NA27344
Resource Type:
Patent
Resource Relation:
Patent File Date: 2015 Jul 10
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 43 PARTICLE ACCELERATORS

Citation Formats

Sridharan, Arun K, Pax, Paul H, Heebner, John E, Drachenberg, Derrek R., Armstrong, James P., and Dawson, Jay W.. Diffractive optical elements for transformation of modes in lasers. United States: N. p., 2016. Web.
Sridharan, Arun K, Pax, Paul H, Heebner, John E, Drachenberg, Derrek R., Armstrong, James P., & Dawson, Jay W.. Diffractive optical elements for transformation of modes in lasers. United States.
Sridharan, Arun K, Pax, Paul H, Heebner, John E, Drachenberg, Derrek R., Armstrong, James P., and Dawson, Jay W.. 2016. "Diffractive optical elements for transformation of modes in lasers". United States. doi:. https://www.osti.gov/servlets/purl/1257998.
@article{osti_1257998,
title = {Diffractive optical elements for transformation of modes in lasers},
author = {Sridharan, Arun K and Pax, Paul H and Heebner, John E and Drachenberg, Derrek R. and Armstrong, James P. and Dawson, Jay W.},
abstractNote = {Spatial mode conversion modules are described, with the capability of efficiently transforming a given optical beam profile, at one plane in space into another well-defined optical beam profile at a different plane in space, whose detailed spatial features and symmetry properties can, in general, differ significantly. The modules are comprised of passive, high-efficiency, low-loss diffractive optical elements, combined with Fourier transform optics. Design rules are described that employ phase retrieval techniques and associated algorithms to determine the necessary profiles of the diffractive optical components. System augmentations are described that utilize real-time adaptive optical techniques for enhanced performance as well as power scaling.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 6
}

Patent:

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  • Spatial mode conversion modules are described, with the capability of efficiently transforming a given optical beam profile, at one plane in space into another well-defined optical beam profile at a different plane in space, whose detailed spatial features and symmetry properties can, in general, differ significantly. The modules are comprised of passive, high-efficiency, low-loss diffractive optical elements, combined with Fourier transform optics. Design rules are described that employ phase retrieval techniques and associated algorithms to determine the necessary profiles of the diffractive optical components. System augmentations are described that utilize real-time adaptive optical techniques for enhanced performance as well asmore » power scaling.« less
  • Vertical-cavity surface-emitting lasers (VCSELs) are very desirable sources for a variety of optical system applications. In particular, the inherent planarity of arrays of VCSELs makes them ideal for compact 3-dimensional optical interconnect systems. Despite smaller beam divergence than edge emitting lasers, spreading of the beam emerging perpendicular to the surface of the VCSEL limits the range of free space transmission, reduces the device density in an array and can introduce cross-talk. Although an external optical system using a separate lens array is a possible solution, the idea may be impractical or expensive due to constraints such as space limitations ormore » the additional need for an optomechanical system to position the lenses. An alternative approach is the integration of high efficiency diffractive optics and VCSELs on a single transparent substrate. Such a compact source is also very attractive for miniature optical instrumentation applications. Integrating diffractive optical elements with substrate-emitting VCSELs provides a method for manipulating the propagation properties of the exiting beams. With diffractive structures, a broad range of optical elements can be easily designed and fabricated and high diffraction efficiencies can be achieved with current processing technologies.« less
  • A sensing element, a method of making a sensing element, and a fiber optic sensor incorporating the sensing element are described. The sensor can be used for the quantitative detection of NO.sub.2 in a mixture of gases. The sensing element can be made by incorporating a diazotizing reagent which reacts with nitrous ions to produce a diazo compound and a coupling reagent which couples with the diazo compound to produce an azo dye into a sol and allowing the sol to form an optically transparent gel. The sensing element changes color in the presence of NO.sub.2 gas. The temporal responsemore » of the absorption spectrum at various NO.sub.2 concentrations has also been recorded and analyzed. Sensors having different design configurations are described. The sensing element can detect NO.sub.2 gas at levels of parts per billion.« less
  • The authors describe the microfabrication of a multi-level diffractive optical element (DOE) onto a micro-electromechanical system (MEMS) as a key element in an integrated compact optical-MEMS laser scanner. The DOE is a four-level off-axis microlens fabricated onto a movable polysilicon shuttle. The microlens is patterned by electron beam lithography and etched by reactive ion beam etching. The DOE was fabricated on two generations of MEMS components. The first generation design uses a shuttle suspended on springs and displaced by a linear rack. The second generation design uses a shuttle guided by roller bearings and driven by a single reciprocating gear.more » Both the linear rack and the reciprocating gear are driven by a microengine assembly. The compact design is based on mounting the MEMS module and a vertical cavity surface emitting laser (VCSEL) onto a fused silica substrate that contains the rest of the optical system. The estimated scan range of the system is {+-}4{degree} with a spot size of 0.5 mm.« less