High-resolution Terahertz Spectroscopy with Quantum-Cascade Lasers
The goal of this project consists in the demonstration of a spectrometer for high-resolution laser spectroscopy of semiconductors at THz frequencies based on narrow-line-width quantum-cascade lasers (QCLs). One target is to determine the line width and line shape of impurity transitions in isotope-pure Ge and Si with ultimate accuracy, i.e. without limitation of the spectral resolution by the apparatus function of the spectrometer. A special focus will be the complementary analysis of the lifetimes derived from time-resolved pump-probe techniques and spectrally resolved absorption measurements with the QCL-based spectrometer. The project is realized in collaboration with the Paul-Drude-Institut (PDI) in Berlin, where dedicated QCLs are developed.
This project is funded by the Deutsche Forschungsgemeinschaft.
(a) Energy level diagram of Si doped with phosphorus (inset) and laser emission from an optically pumped Si:P THz laser [A. Borak, Science 308, 638 (2005)]. (b) Infrared absorption spectrum of 28Si doped with boron and (residual) phosphorus [M. Steger et al., Phys. Rev. B 79, 205210 (2009)].
Contact: M. Wienold, H.-W. Hübers