Dr. S. Roger Qiu Profile

Dr. S. Roger Qiu

Scientist at Lawrence Livermore National Lab

SPIE Involvement:

Author

Publications (11)

Proceedings Article | 3 December 2022 Presentation

Identifying, understanding, and suppressing of ns laser damage precursors in dielectric thin films

S. Roger Qiu, Colin Harthcock, Raluca Negres, Chris Stolz, Gabe Guss, Vanessa Peters, Paul Mirkarimi, Eyal Feigenbaum, Thomas Voisin, Josh Hammons, Chris Colla, Harris Mason, Mengbing Huang

Proceedings Volume PC12300, PC123000P (2022) https://doi.org/10.1117/12.2642498

KEYWORDS: Laser induced damage, Dielectrics, Thin films, Optical coatings, Ultraviolet radiation, Thin film coatings, Systems modeling, Sputter deposition, Pulsed laser operation, Monte Carlo methods

Read Abstract +

Proceedings Article | 12 October 2021 Presentation

Impact of film densification on UV-ns laser damage performance for MLD coatings

Colin Harthcock, S. Roger Qiu, Paul Mirkarimi, Thomas Voisin, Christopher Colla, Harris Mason, Raluca Negres, Gabe Guss, Devika Vipin, Mengbing Huang

Proceedings Volume 11910, 119100X (2021) https://doi.org/10.1117/12.2600525

KEYWORDS: Xenon, Sputter deposition, Ion beams, Argon, Laser induced damage, Hafnium, Resistance, Reflection, Optical coatings, Metals

Read Abstract +

Proceedings Article | 11 September 2020 Presentation

Towards understanding the difference in ultraviolet, ns-laser damage resistance between hafnia films produced by electron beam evaporation and ion beam sputtering methods

Vanessa Peters, S. Roger Qiu, Colin Harthcock, Raluca Negres, Thomas Voisin, Eyal Feigenbaum, Gabe Guss, Christopher Stolz, M. Huang

Proceedings Volume 11514, 1151416 (2020) https://doi.org/10.1117/12.2572814

KEYWORDS: Laser induced damage, Ultraviolet radiation, Resistance, Electron beams, Ion beams, Sputter deposition, Deposition processes, Dielectrics, Refractive index, Laser development

Read Abstract +

It is well known that dielectric coatings used in high energy laser systems for beam steering are susceptible to laser damage. The laser damage ensued in high refractive index materials, such as hafnia, is responsible for limiting the laser operation fluence and lifetime. Although hafnia is an ideal high refractive index material used in dielectric coatings for a broad range of laser wavelengths, defects developed during the deposition process leads to laser-induced damage. In order to increase the resistance to laser damage and improve laser performance, it is imperative to understand the underlying physics of laser damage in high index coating materials. Earlier work observed a substantial difference in laser damage thresholds for hafnia coatings produced by different deposition methods, yet the underlying mechanisms for the observed difference remains elusive. In this work we investigated the responses of single layer hafnia films produced by two deposition processes, electron beam (e-beam) evaporation and ion beam sputtering (IBS) methods upon UV ns-laser exposure. The films underwent laser damage testing using a 1-on-1 laser damage testing protocol with a beam size of 650 µm (1/e2) at 355 nm and 8 ns pulse duration. Both S and P polarizations were tested at a 45° angle of incidence. Chemical, structural and morphological characterizations of the films both pre- and post-laser damage were performed using Rutherford backscattering spectroscopy, glancing incidence X-Ray diffraction, and optical and scanning/transmission electron microscopy. We found that films deposited from the e-beam process had a higher damage onset threshold (4.4 +/- 0.1 J/cm2) than those deposited by IBS method (2.1 +/- 0.2 J/cm2). Furthermore, a polarization-dependent damage threshold onset was observed for the e-beam evaporated coatings but was not observed in IBS films. Although the typical size of the damage in general is larger for the e-beam produced films, the morphology shows similar foamy appearance in both films. The density of the damage sites, on the other hand, was much greater in the IBS produced films than that by the e-beam method. The observed difference can be attributed to their resulting structural/textural differences inherited in each method: porous in the e-beam films and dense with isolated nanobubbles in the IBS films, which can lead to a large difference in laser-defect coupling. The underlying physical mechanism will be discussed in detail. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. IM Release# LLNL-ABS-809117

Proceedings Article | 11 September 2020 Presentation

The effect of low temperature annealing on the UV, ns laser damage performance of hafnia single layers

Colin Harthcock, Roger Qiu, Raluca Negres, Gabe Guss, Gourav Bhowmik, Mengbing Huang

Proceedings Volume 11514, 1151410 (2020) https://doi.org/10.1117/12.2572175

KEYWORDS: Laser induced damage, Annealing, Ultraviolet radiation, Laser systems engineering, Optical coatings, Oxygen, Chemical analysis, Multilayers, Dielectrics, Laser applications

Read Abstract +

Proceedings Article | 26 November 2019 Presentation

The impact and origins of non-stoichiometry on the laser performance of ion beam sputtering deposited hafnia films (Conference Presentation)

Colin Harthcock, Roger Qiu, Paul Mirkarimi, Raluca Negres, Gabe Guss, Marlon Menor, Gourav Bhowmik, Mengbing Huang

Proceedings Volume 11173, 111730Q (2019) https://doi.org/10.1117/12.2537142

KEYWORDS: Planets, Chemistry, Sun, Argon, Ion beams, Optical damage, Multilayers, Dielectrics, Optical coatings, High power lasers

Read Abstract +

Proceedings Article | 5 June 2018 Paper

Transport mirror laser damage mitigation technologies on the National Ignition Facility

Christopher Stolz, S. Roger Qiu, Raluca Negres, Issac Bass, Phil Miller, David Cross, James Davis, Stanley Sommer, Clay Widmayer, Brian MacGowan, Pamela Whitman, Paul Wegner

Proceedings Volume 10691, 106910W (2018) https://doi.org/10.1117/12.2323284

KEYWORDS: Mirrors, Laser induced damage, National Ignition Facility, Particles, Backscatter, Plasma, Optical coatings, Laser optics, Reflection

Read Abstract +

Proceedings Article | 6 December 2016 Open Access

Laser-matter coupling mechanisms governing particulate-induced damage on optical surfaces

M. Matthews, E. Feigenbaum, S. Demos, R. Raman, S. R. Qiu, N. Shen, C. Harris, R. Negres, M. Norton, D. Cross, A. Rubenchik

Proceedings Volume 10014, 1001402 (2016) https://doi.org/10.1117/12.2244981

KEYWORDS: Near field optics, Particles, Pulsed laser operation, Plasma, Silica, Aluminum, Scattering, Laser scattering, Light scattering, Metals

Read Abstract +

DOWNLOAD PAPER

Proceedings Article | 14 December 2015 Paper

Impact of particle shape on the laser-contaminant interaction induced damage on the protective capping layer of 1high reflector mirror coatings

S. Qiu, M. Norton, J. Honig, A. Rubenchik, C. Boley, A. Rigatti, C. Stolz, M. Matthews

Proceedings Volume 9632, 963208 (2015) https://doi.org/10.1117/12.2195517

KEYWORDS: Optical spheres, Particles, Silica, Laser induced damage, Plasma, Spherical lenses, Mirrors, Multilayers, Reflectors, Cameras

Read Abstract +

Proceedings Article | 6 December 2010 Paper

Impact of substrate surface scratches on the laser damage resistance of multilayer coatings

S. Roger Qiu, Justin Wolfe, Anthony Monterrosa, William Steele, Nick Teslich, Michael Feit, Thomas Pistor, Christopher Stolz

Proceedings Volume 7842, 78421X (2010) https://doi.org/10.1117/12.867740

KEYWORDS: Multilayers, Laser induced damage, Resistance, Optical coatings, Laser damage threshold, Silica, Mirrors, Etching, Dielectrics, Surface finishing

Read Abstract +

Proceedings Article | 31 December 2009 Paper

Modeling of light intensification by conical pits within multilayer high reflector coatings

S. Roger Qiu, Justin Wolfe, Anthony Monterrosa, Michael Feit, Thomas Pistor, Christopher Stolz

Proceedings Volume 7504, 75040M (2009) https://doi.org/10.1117/12.836916

KEYWORDS: Multilayers, Coating, Silica, Laser induced damage, Computer simulations, Finite-difference time-domain method, Waveguides, Mirrors, High reflection coatings, Resistance

Read Abstract +

Proceedings Article | 31 December 2009 Paper

Laser damage resistant pits in dielectric coatings created by femtosecond laser machining

Justin Wolfe, Roger Qiu, Christopher Stolz, Michael Thomas, Carolyn Martinez, Arzu Ozkan

Proceedings Volume 7504, 750405 (2009) https://doi.org/10.1117/12.836906

KEYWORDS: Laser induced damage, Femtosecond phenomena, Dielectrics, Laser damage threshold, Mirrors, Optical coatings, Multilayers, Prototyping, Raster graphics, Laser systems engineering

Read Abstract +

Showing 5 of 11 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years