February 27, 2013
Glenn Roberts Jr.
“In less than a decade, SLAC has built up an impressive array of dozens of laser systems – and a team of laser scientists and engineers – with capabilities that make it one of the most cutting-edge national laboratories under the U.S. Department of Energy.
Joe Robinson, a staff scientist, at left, works with Mike Minitti, group leader for LCLS-related lasers, on a laser system to be used in an LCLS experiment. (Credit: Matt Beardsley)
Conventional optical lasers require three components: 1) a “pump source,” such as a flashlamp or other laser that provides an energy source; 2) a “lasing medium,” such as a specialized crystal that amplifies light; and 3) an “optical resonator,” which is a cavity with two end mirrors, one an end mirror that is highly reflective and the other an output mirror that partially transmits light, allowing light to circulate within the resonator. [Click thumbnail for full view.] (Laser components description courtesy of Mike Woods/SLAC. Laser diagram courtesy of Lakkasuo/Wikimedia Commons)
Lighting the way
SLAC’s newfound laser focus took shape with the 2005 hire of Bill White, a laser expert who had worked at Lawrence Livermore National Laboratory and in private enterprise. White was hired to help the lab prepare for the 2009 launch of the Linac Coherent Light Source, a unique X-ray laser with ultrabright, ultrashort pulses that requires more conventional lasers for most experiments.
The lab’s inventory of 135 high-power optical lasers includes 40 lasers that can be used in LCLS experiments. Another 18 lasers are installed at the LCLS injector, where they produce the beam of electrons that is converted into X-ray pulses.
There are 25 laser facilities at SLAC, and their laser systems serve in a variety of roles in experiments: aligning molecules in the same direction and orientation, shocking and compressing matter, switching magnetic states and exciting chemical reactions, as examples.
The lasers often incorporate off-the-shelf commercial components, though SLAC’s specialization in studying ultrafast processes, which can be measured in trillionths to quadrillionths of a second, requires customization, White said.
SLAC’s laser systems, at their core, represent ‘controlled energy that can interact with matter in countless ways,’ said Alan Fry, deputy director of SLAC’s Laser Science and Technology Division. “They allow us to stimulate very specific changes in materials and to probe and measure those changes with extreme precision.’”
See the full article here.
SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.
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