Lawrence Livermore National Laboratory



Our goal is to understand how physical properties and defects contribute to laser-induced damage in dielectric and conductive coatings, as well as to develop strategies to fabricate high-performance coatings for a wide variety of laser applications.

Multilayer dielectric coatings



A full aperture optic for laser application at 1053 nm made from multilayer dielectric coating thin film by e-beam physical vapor deposition..

Multilayer dielectric coating films produced by either e-beam physical vapor deposition or ion beam sputtering deposition methods are frequently used in high energy and high power laser systems. The utilization of alternative high and low index material coatings not only enables extremely high optical reflectivity but also preserves laser resistance in optical components. However, the laser performance of dielectric coatings can often be degraded by coating defects, surface contaminations and substrate surface-flaws. Continued efforts have been made to identify and understand precursors that are responsible to laser induced damage in the films. Mitigation strategies and process protocol are also being developed based on the fundamental studies. The ultimate aim is to develop robust dielectric coating films for laser systems that are operated at a lower wavelength and higher fluence beyond the current technology.




 

S.R. Qiu, M.A. Norton, J. Honig, A.M. Rubenchik, C.D. Boley, A. Rigatti, C.J. Stolz, M.J. Matthews, “ Shape dependence of laser-particle interaction-induced damage on the protective capping layer of 1 omega high reflector mirror coatings”, Optical Engineering, 56 (2017) 011108

R.A. Negres, C.W. Carr, T.A. Laurence, K. Stanion, G. Guss, D.A. Cross, P.J. Wegner, C.J. Stolz, “Laser-induced damage of intrinsic and extrinsic defects by picosecond pulses on multilayer dielectric coatings for petawatt-class lasers”, Optical Engineering, 56 (2017) 011008

S.R. Qiu, M.A. Norton, R.N. Raman, A.M. Rubenchik, C.D. Boley, A. Rigatti, P.B. Mirkarimi, C.J. Stolz, M.J. Matthews, “Impact of laser-contaminant interaction on the performance of the protective capping layer of 1 omega high-reflection mirror coatings”, Applied Optics, 54 (2015) 8607

S.R. Qiu, J.E. Wolfe, A.M. Monterrosa, M.D Feit, T.V. Pistor, C.J. Stolz, “Searching for optimal mitigation geometries for laser-resistant multilayer high-reflector coatings”, Applied Optics, 50 (2011) C373

J.E. Wolfe, S.R. Qiu, C.J. Stolz, “Fabrication of mitigation pits for improving laser damage resistance in dielectric mirrors by femtosecond laser machining”, Applied Optics, 50 (2011) C457

S.R. Qiu, J.E. Wolfe, A.M. Monterrosa, M.D Feit, T.V. Pistor, C.J. Stolfz, “Searching for optimal mitigation geometries for laser-resistant multilayer high-reflector coatings”, Applied Optics, 50 (2011) C373

J.E. Wolfe, S.R. Qiu, C.J. Stolz, “Fabrication of mitigation pits for improving laser damage resistance in dielectric mirrors by femtosecond laser machining”, Applied Optics, 50 (2011) C457

J.-H. Yoo, M. G. Menor, J. J. Adams, R. N. Raman, J. R. I. Lee, T. Y. Olson, N. Shen, J. Suh, S. G. Demos, J. Bude, and S. Elhadj, "Laser damage mechanisms in conductive widegap semiconductor films," Opt. Express 24, 17616-17634 (2016).

S. Elhadj, J.-h. Yoo, R. A. Negres, M. G. Menor, J. J. Adams, N. Shen, D. A. Cross, I. L. Bass, and J. D. Bude, "Optical damage performance of conductive widegap semiconductors: spatial, temporal, and lifetime modeling," Opt. Mater. Express 7, 202-212 (2017).

J.-H. Yoo, A. Lange, J. Bude, and S. Elhadj, "Optical and electrical properties of indium tin oxide films near their laser damage threshold," Opt. Mater. Express 7, 817-826 (2017).

A. P. Lange, A. Samanta, H. Majidi, S. Mahajan, J. Ging, T. Y. Olson, K. van Benthem, and S. Elhadj, "Dislocation mediated alignment during metal nanoparticle coalescence," Acta Materialia 120, 364-378 (2016).


Transparent conductive films

Our thin film studies are aimed at gaining a fundamental understanding of how transparent conductive film properties such as microstructures, defects, conductivity, and carrier mobility contribute to optical damage performance and lifetime. Specifically, how these parameters relate to materials, fabrication processes, and to enhanced laser annealing conditions including methods for defect reduction in wide gap semiconductors. Ultimately, we aim to deliver transparent conductive electrodes and fabrication methods for next generation, compact, high rep rate, and high power laser systems by focusing on understanding damage mechanisms and relationship with processing, structure, properties that are essential for addressing use of optoelectronics in high performance rep-rated lasers.

Microscope images of pulsed laser irradiation (λ=1064nm) damage and removal of a transparent conductive oxide film. Insets show surface structuring from apparent optical interference effects and the picture of a test sample after controlled laser exposure conditions.