2014 R&D 100 Winner
EXUDEEfforts to scale the power of a single-output laser to more than 100 kW have encountered significant challenges in removing waste heat, maintaining beam quality and avoiding optical damage to output optics. Electrically driven solid-state lasers have been demonstrated at this power level, but the thermo-optical distortions in the bulk laser materials demonstrated to date result in degraded beam quality, which limits the irradiance delivered to a target.

Spectral beam combining (SBC) of fiber lasers offers a straightforward approach for power scaling. The approach exploits the broad gain bandwidth to enable large numbers of fiber laser channels to be combined with near-diffraction-limited beam quality. Rigorous application of SBC has allowed a development team including Lawrence Livermore National Laboratory, Lockheed Martin Laser and Sensor Systems and Advanced Thin Films to develop the EXtreme-power, Ultra-low-loss, Dispersive Element (EXUDE) optical element, the first-ever electrically efficient, near diffraction-limited 30-kW beam combined laser. Key underlying technologies include proprietary optical coating designs using more than 100 thin-film layers that enable ultra-low-loss transmission levels. This and other enabling technologies, such as dispersive surface relief structure design, allow single 30-kW beams of light at more than 98% efficiency, and project maximum output of more than 100 kW.

Near diffraction-limited 30-kW beam combined laser

Lawrence Livermore National Laboratory
Lockheed Martin Laser and Sensor Systems
Advanced Thin Films

Development Team

The EXtreme-power, Ultra-low-loss, Dispersive Element (EXUDE) Development Team
Jerry A. Britten, Principal Developer, Lawrence Livermore National Laboratory
Eric Honea, Principal Developer, Lockheed Martin Laser and Sensor Systems
Ramin Lalezari, Principal Developer, Advanced Thin Films
Michael D. Aasen, Lawrence Livermore National Laboratory
Robert Afzal, Lockheed Martin Laser and Sensor Systems
Jeffrey Cao, Lockheed Martin Laser and Sensor Systems
Thomas C. Carlson, Lawrence Livermore National Laboratory
Howard Champoux, Advanced Thin Films
Mark Feldman, Lockheed Martin Laser and Sensor Systems
Curly R. Hoaglan, Lawrence Livermore National Laboratory
Dan Hu, Lockheed Martin Laser and Sensor Systems
Don Jander, Lockheed Martin Laser and Sensor Systems
Cindy C. Larson, Lawrence Livermore National Laboratory
Hoang T. Nguyen, Lawrence Livermore National Laboratory
James D. Nissen, Lawrence Livermore National Laboratory
Tracy Vatter, Lockheed Martin Laser and Sensor Systems