By Emily Hubbell

Dr. P. Gregory Van Patten, Dr. Jeffrey Rack and Dr. Eric Stinaff are three of five co-Principal Investigators on a recent National Science Foundation instrumentation grant. (Photo by Lydia Deakin)


In the amount of time it takes for light to travel a mere one third of a micrometer, one femtosecond has already come and gone. A femtosecond—which clocks in at the length of one billionth of one millionth of a single second—is measured as 10 to the -15th power.

Although a femtosecond doesn’t last very long, there’s a lot going on at this timescale. Investigations at a femtosecond resolution can reveal key details behind phenomena that nano scientists have yet to fully understand,including the energy dissipation process, the photochemical event of vision and the change in an electron’s properties.

"You’re looking at timescales in which electrons relax inside nanostructures, where spins interact,"said Dr. Eric Stinaff, assistant professor of physics. "How do charges relax and get into their final state? That’s still an open question."

To help understand these processes, the National Science Foundation recently awarded four NQPI members $400,000 for a new ultrafast transient absorption spectrometer.

The five co-Principle Investigators on the grant are NQPI members Dr. Tadseuz Malinski, Dr.Jeffrey Rack, Dr. Stinaff and Dr. P Gregory Van Patten; and Dr.Jennifer Hines.

The spectrometer operates like a strobe light. After a molecule is hit with one laser, another pulse of light is sent through. The delay between the two beams is at a femtosecond resolution, allowing researchers to observe changes in the sample that happen during this ultrafast timeframe.

"There’s a lot of interesting chemistry and physics to be done at the femtosecond time scale," Dr. Stinaff said.

The device has a large range of excitation and detection wavelengths that make it adaptable to many different experiments. In the future, students will be trained to operate the spectrometer, Dr. Rack said.