Utilizing some of the most powerful laser systems in the world, Harvey Mudd researchers will create and study some of the smallest specimens.<\/p>\n
Physics Professor Tom Donnelly specializes in high-intensity, laser-matter interactions. In short, he points lasers at sub-micron targets, blasts them into plasma and studies the resulting particle properties and deposited energy.<\/p>\n
In the past 20 years, he and his students have worked with physicist Todd Ditmire, high-powered laser inventor and director of the High-Intensity Laser Science Group at the University of Texas in Austin. Now, Donnelly and Ditmire have been awarded a $255,000, three-year National Science Foundation grant to answer the question, \u201cBy what mechanism do high-intensity laser pulses deposit energy into a wavelength-scale target?\u201d<\/p>\n
The research will help advance basic plasma physics and may have possible applications in developing better X-ray and neutron sources for radiography and in serving as a test bed for fusion research.<\/p>\n
\u201cThe interaction of the laser pulse with a small target has the potential for coupling large amounts of energy into small volumes so you can get incredibly hot, dense sources, which can generate particles such as neutrons and X-rays,\u201d said Donnelly.<\/p>\n
Donnelly and his student researchers are working on a device that deposits sub-micron-sized polystyrene spheres onto a silicon surface. They\u2019ll use a 1-megawatt laser to eject the particles from the silicon and, as the particles move out from the surface, they\u2019ll hit them with a 20-terawatt laser and record the energy spectra of the resulting electrons.<\/p>\n
The pulse of the 20-terawatt laser has nearly 10 times the power of the nation\u2019s electrical grid. The polystyrene spheres are half-micron and smaller in diameter\u2014tiny targets, considering the diameter of an average human hair is about 50-100 microns.<\/p>\n
\u201cWe have a model that suggests how to optimize the amount of energy Todd\u2019s high-power laser can deposit into small targets. To test the model, we\u2019ll record the energy of electrons that result from the laser-target interaction as we change target size and laser power,\u201d Donnelly said.<\/p>\n
Donnelly and his research students will build the machine that will deliver the targets to the focus of the high-power laser. They will also travel to the University of Texas to participate in the laser-target interaction experiments.<\/p>\n","protected":false},"excerpt":{"rendered":"
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