Paper 13358-19
Paper 13358-19
The advent of third-harmonic-generation laser systems: personal recollections (Invited Paper)
28 January 2025 • 10:30 AM - 11:00 AM PST | Moscone South, Room 76 (Lower Mezz)
Abstract
In the mid to late 1970s there was considerable debate as to which laser technology should be pursued—glass lasers (1-µm wavelength) or CO2 lasers (10 µm). Based on target physics considerations, theorists were advocating for shorter wavelengths. The physics understanding was confirmed by exciting results from the group at Ecole Polytechnique, who observed close to 100% target absorption with just a few joules of fourth-harmonic energy. These results motivated the leadership at LLE to plan similar experiments at the third harmonic with a few more joules. This presentation covers a small time period from 1979 to 1980 during which highly efficient third-harmonic generation (THG) became understood theoretically and demonstrated experimentally, leading to the worldwide adoption of THG with glass lasers for fusion research.
This material is based upon work supported by the Department of Energy [National Nuclear Security Administration] University of Rochester “National Inertial Confinement Fusion Program” under Award Number DE-NA0004144.
Presenter
R. Stephen Craxton
Univ. of Rochester (United States)
Stephen Craxton is a Distinguished Scientist in the Theory Division at the University of Rochester’s Laboratory for Laser Energetics (LLE). He came to LLE in 1976 after completing his Ph. D. at Imperial College, London, to work on the computer modeling of laser-matter interactions. In 1980, he discovered how to efficiently triple the frequency of high-power lasers to the ultraviolet to make them more effective for fusion research. His designs were incorporated into the 24- and 60-beam OMEGA laser systems and the National Ignition Facility (NIF). He is the first author of a major review of direct drive published in Physics of Plasmas in 2015. Since 1998 he has directed the unique LLE Summer High-School Research Program, in which local students work in the summer after their junior years under the guidance of LLE scientists on projects related to the LLE program. He is a Fellow of the American Physical Society.