Chemistry Professor Develops Fastest Laser System in Gulf South
Louis Haber, assistant professor of chemistry at LSU, has recently established the fastest and most powerful pulsed laser system in the Gulf south. He will use this state-of-the art system to study chemical reactions that occur on the surface of nanoparticles.
“Having a fast laser is analogous to having a camera with a very fast shutter speed that allows these chemical and physical dynamics to be captured and studied on this ultrafast time scale,” said Haber. “If the laser pulse is not shorter than the process you are studying, you can't hope to see it and you'll just get averaged and blurred out results that lack the interesting and important information.”
The laser in Haber’s laboratory produces 75 femtosecond pulses with 4 millijoules per pulse at 1,000 pulses per second, equaling roughly 5 x 1010 Watts per laser pulse. A typical light bulb is only 100 watts or 500,000,000 times dimmer. Chemical and physical processes such bonds breaking and rearranging, molecules vibrating and rotating, and electrons getting excited and then relaxing back down to the ground-state all occur on very short time scales, on the order of femtoseconds (10^-15 s), picoseconds (10^-12 s) and in some cases nanoseconds (10^-9 s).
Secondly, having a short laser pulse also allows us to have a very intense beam of light during the pulse, which allows for nonlinear optical effects to occur, such as photons adding together in the sample.
“The goal of my research is to learn how molecules interact with different materials on the nanoscale,” said Haber. “By focusing extremely short pulses of intense light to nanomaterial samples, we can investigate the properties of molecular absorption and surface charge densities at nanoparticle surfaces. We can also study energy transfer between molecules and nanoparticles for developing better sensors, catalysts and photovoltaics.”
Haber also noted that not only is his laser system the fastest in the Gulf South, it is also faster than anything in Alabama.
He received his bachelor’s and Ph.D. at the University of California at Berkley and conducted postdoctoral research at Columbia University before joining LSU’s Department of Chemistry in August 2012.