MRI-R2: Acquisition of a High-Power Femtosecond Ti:Sapphire Laser for Ultrafast Terahertz Spectroscopy

Macalester College, Saint Paul MN

Investigators

Abstract

0959341 Heyman Macalester College MRI-R2: Acquisition of a High-Power Femtosecond Ti:Sapphire Laser Oscillator for Time-Resolved Terahertz Spectroscopy. Technical Summary: This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). It is increasingly important to understand carrier transport phenomena in electronic materials on picosecond and femtosecond time-scales. We propose to acquire a high-power femtosecond Ti:Sapphire laser oscillator to support characterization of electronic materials at Macalester College. Time-resolved terahertz spectroscopy offers a sub-picosecond probe of conductivity and charge carrier mobility in materials. This application requires a laser producing highly stable, powerful femtosecond laser pulses, and the system requested will provide an ideal balance of laser-power, repetition rate and stability for this purpose. The system will initially be used to study carrier transport in graphene and ultrathin graphite. Graphene, a novel carbon material consisting of a single sheet of carbon atoms, shows exceptional promise as an electronic material. The properties of few-layer graphite are tunable with thickness. The new laser system will also be used to study other electronic materials including semiconductors and semiconductor heterostructures. Our research program will provide education and research training opportunities for advanced undergraduate students in Photonics and experimental Condensed Matter Physics. The PI's research lab has trained 35 advanced undergraduates during the last 15 years. More than two thirds of these students have pursued graduate degrees in Science, Math or Engineering. Layman Summary: This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). As the clock speeds of computers and transistors are pushed ever higher, it becomes increasingly important to understand how electric charge moves in the materials they are made from on ultra short time scales. Time resolved terahertz spectroscopy can track the motion of electric charge over times as short as 1/100th of a trillionth of a second, a ten-thousandth of the interval between computer clock tics. We can map out in time the processes which occur in transistors and photo-switches when they are switched from "off" to "on" with a pulse of light. We propose to acquire a high-power femtosecond Ti:Sapphire laser oscillator to support characterization of novel electronic materials and research training at Macalester College. The system we are requesting will provide an ideal balance of laser-power, repetition rate and stability for time-resolved terahertz spectroscopy. This system will initially be used to study graphene, a novel material consisting of single sheets of carbon atoms which shows exceptional promise as a material for ultra high-speed, nanometer-scale transistors. Our research program will provide education and research training opportunities for advanced undergraduate students in Photonics and experimental Condensed Matter Physics. The PI's research lab has trained 35 advanced undergraduates during the last 15 years. More than two thirds of these students have pursued graduate degrees in Science, Math or Engineering.