Carbon nanotubes are one-dimensional conductors, meaning that quantum mechanics forces the transverse excitations of the nanotube to be at such high energies that they are not accessible even at room temperature. These one-dimensional conductors are predicted to have a plasma resonance, which is a collective mode in which the electrons "slosh" back and forth longitudinally (along the length of the tube). This resonant frequency depends on the length of the nanotube, and it has been observed at far-infrared frequencies, but it has not yet been observed for longer tubes at lower frequencies (GHz and THz). These lower frequencies can be accessed via time-domain terahertz spectroscopy. The student will learn to use this spectroscopy apparatus and will make measurements on a carbon nanotube film. Because this experiment has a steep learning curve, requiring the student to incorporate optics, short-pulse lasers, electronics, computer interfacing with equipment, and solid-state physics, it would be most appropriate for a rising senior who will continue the project in Physics 410.
Experience in optics, programming, and computer interfacing with equipment will be useful.