22-25 September 2013
NIST, Boulder, Colorado, USA
SPIE Laser Damage -- the leading forum on optical materials for high-power/high-energy lasers -- drew nearly 150 international participants to the NIST (National Institute of Standards and Technology) facility in Boulder for a week of technical presentations and discussions and valuable networking events.
This year's event was the 45th in the series showcasing a technology with wide-ranging applications in industrial materials processing, remote sensing, large-scale displays, surgery, anti-missile weapons, laser-induced nuclear fusion, and fundamental research. The conference was co-sponsored by Lawrence Livermore National Lab and Spica Technologies.
Conference chair Detlev Ristau (Laser Zentrum Hannover) noted that the number of papers was slightly up over 2012, and that the continuing high quality of the submissions is a clear indicator of the efforts of groups all over the world. (For more detail about the research presentations, read excerpts from Ristau's notes on the meeting [PDF 316 KB].)
Below, participants pause outside the offices of the National Center for Atmospheric Research for an annual group photo.
Discussion in the round
Effects of laser field enhancement in laser-induced damage were discussed at the pre-symposium roundtable Sunday evening in the Boulder Marriott Hotel. Major focus was on relations between field enhancements and the amount of laser fluence calculated from measured pulse energy divided by laser-spot area. Moderators were conference chairs M.J. Soileau and Vitaly Gruzdev.
A welcome reception following the roundtable drew strong attendance.
Opening with a brief look back
Vitaly Gruzdev (University of Missouri-Columbia) opened conference sessions Monday in the Radlo Building at NIST with a brief look at the history of the 45-year-old event.
Chairs of the conference along with Gruzdev are Gregory Exarhos (Pacific Northwest National Lab), Joseph Menapace (Lawrence Livermore National Lab), Detlev Ristau (Laser Zentrum Hannover) and M.J. Soileau (University of Central Florida Office of Research and Commercializaton).
First organized by Art Guenther and Alex Glass, the conference continues to be an important forum to overcome challenges around laser-induced damage in optical materials.
Conference presentations and discussions have made significant contributions to the fundamental understanding of laser damage and the development of optical components with improved power handling capability.
Honors for outstanding work
Chair Joseph Menapace presented awards for the 2012 Best Oral Presentation and Best Poster Presentation.
Above, Carmen Menoni, professor of electrical and computer engineering and director of the Advanced Thin Flim Lab at Colorado State University, accepted the 2012 Best Paper Award, for "What role do defects play in the laser damage behavior of metal oxides?" Co-authors include other researchers from Colorado State as well as from the University of New Mexico and Stanford University. Menoni's work is supported by the Office of Naval Research and the Department of Defense High-Energy Lasers Joint Technology Office.
Gintarė Batavičiūtė (above) accepted the 2012 Best Poster Presentation award on behalf of a team from Vilnius University, for "Bayesian approach of laser-induced damage threshold analysis and determination of error bars."
Several plenary talks were presented in well-attended sessions throughout the week:
- Defect insensitive 100 J/cm2 multilayer mirror coating process, Christopher Stolz (Lawrence Livermore National Lab), et al.
- National Ignition Facility laser performance: status and thoughts on future capabilities, Paul Wegner (Lawrence Livermore National Lab)
- A review of laser target debris and shrapnel studies by AWE, James Andrew (AWE)
- Power limits of narrow-linewidth Raman fiber lasers, Mike Klopfer (University of New Mexico), et al.
- Laser damage in dielectric films: What we know and what we don't, Wolfgang Rudolph (University of New Mexico), et al.
Thin film damage test: the results
The 2013 Thin Film Damage Competition was a continuation of the 2013 competition: 1064 nm thin film Brewster angle plate polarizers were damage tested (10 ns pulse duration) in "P" polarization in 2012 and in "S" polarization in 2013.
A total of 31 samples were received from 17 different institutions that resided in 6 different countries, reported program committee member Christopher Stolz (Lawrence Livermore National Lab).
The most obvious trend was that for each sample, the "S" polarization laser damage threshold was always higher than the "P" polarization laser damage threshold. This behavior is consistent with the standing wave electric field profile which has higher magnitude and deeper electric field penetration in "P" polarization than in "S" polarization, Stolz said.
Like previous damage competitions, the coating materials and coating deposition methods also had an impact on coating laser resistance. Coatings consisting of hafnia and silica tended to have higher laser resistance and e-beam or e-beam with ion assist also tended to have higher laser resistance.
This series of thin film damage competitions is a double blind test to protect the identity of the participants with the intention of sampling the current capabilities of the thin film community and to observe general laser damage trends.
Several companies and institutes from the USA, Europe, China, and Japan sent in samples which were tested at the laser-damage test facility of Quantel, USA.
For the upcoming laser damage conference in 2014, a thin film Fabry-Perot filter for the Nd:YAG-laser wavelength damage tested in the ns-regime will be considered.
Overviews and one-on-one
Poster sessions on Monday and Tuesday were preceded by brief overview presentations in the conference room.
An open house sponsored by local firms ATFilms and Precision Photonics brought conference participants together on Monday evening.
A night out
Attendees enjoyed a wine- and cheese-tasting reception on Tuesday evening at NCAR hosted by SPIE and the Laser Damage co-chairs, with contributing sponsor for food and drink Arrow Thin Films.
Take it to the limits
"To High-Power Limits of Fiber Lasers" was the topic of Wednesday's mini-symposium, chaired by Leonid Glebov (CREOL, College of Optics and Photonics, University of Central Florida) and Jonathan Arenberg (Northrop Grumman Aerospace Systems).
Nikolai Platonov of IPG Photonics gave a keynote talk on "Feasibility of maximum achievable powers and energies in fiber lasers," discussing results on the damage behavior of polished and cleaved fiber end faces.
A study on cw laser damage at 405 nm presented by Cornell Gonschior (Technische Hochschule Mittelhessen) indicated the formation of a ripple structure and color centers in the core region of the fiber leading to losses not acceptable for the application.
Already looking ahead to next year!
Conference chairs were already planning for Laser Damage 2014 by week's end. From left above are Vitaly Gruzdev (University of Missouri-Columbia), Joseph Menapace (Lawrence Livermore National Lab), M.J. Soileau (University of Central Florida Office of Research and Commercializaton), Gregory Exarhos (Pacific Northwest National Lab), and Detlev Ristau (Laser Zentrum Hannover)
Below, at view of the University of Colorado, Boulder, against the backdrop of the Flatiron Mountains.