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Humboldt-Universität zu Berlin - Faculty of Mathematics and Natural Sciences - Optical Systems

Humboldt-Universität zu Berlin | Faculty of Mathematics and Natural Sciences | Department of Physics | Optical Systems | Projects | High-resolution Terahertz Spectroscopy with Quantum-Cascade Lasers

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.

 

thz-spectroscopy-with-qcls.text.image0

(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