Advanced Light Sources

Recent advances in ultrashort-pulse laser technology and nonlinear optical techniques for frequency conversion now allow to produce laboratory radiation sources at virtually any wavelength all the way from the submillimeter (T-ray) to the nano- and even picometer (X-ray) range, spanning some 9 orders of magnitude! Currently, there is no alternative way of achieving comparable spectral coverage, not even at large-scale synchrotron or free-electron laser facilities. Once becoming sufficiently powerful, femtosecond-laser-driven radiation sources hold promise for offering significant relative as well as absolute values. Many industrial, medical, and scientific applications of powerful radiation that are currently bound to large-scale facilities may find their way into small university and industrial laboratories owing to the compactness of these sources. This is a relative value. On the other hand, femtosecond-laser-driven sources generate pulses inherently synchronized all the way from the far infrared to the X-ray regime. The pulses can be shorter and/or have higher peak intensities than achievable with any other source. These unique capabilities offer the potential for developing novel spectroscopic and other techniques for scientific, industrial or medical use, constituting an absolute value. Nevertheless, frequency-shifted femtosecond-laser-pumped sources must be significantly improved before this enormous potential in terms of either relative or absolute values can be exploited. Although nonlinear frequency conversion techniques offering the above spectral coverage have already been successfully demonstrated, the low power levels attainable with current-generation femtosecond-laser-pumped sources restrict applications to a few selected areas. The central objective of the research program presented in this proposal is the exploitation of the above described potential. The mission of the Spezialforschungsbereich Advanced Light Sources (ADLIS) includes goals in science, engineering, and education: Significantly advance the state of the art of generating ultrashort optical wave packets, laboratory THz (T-ray), and laboratory short-wavelength (XUV/X-ray) sources by drawing on cutting-edge femtosecond laser technology. Use of the advanced sources for pushing the frontiers of experimental physics, developing new sophisticated ultrafast spectroscopies, and laboratory techniques for microanalysis. Broadly train and educate scientists in interdisciplinary research areas. State-of-the-art femtosecond Ti:sapphire lasers will constitute the major "work horse" for realizing the SRP objectives. Novel techniques will be developed for significantly improving peak power, quality and controllability (shape and absolute phase control) of few-cycle (sub-10fs) pulses delivered by cutting-edge ultrafast laser systems. These systems are expected to significantly improve the state of the art of both THz and XUV/X-ray femtosecond- laser-driven sources in terms of both average and peak brightness. After their development and characterization, these advanced light sources will be used for pushing the frontiers of existing and developing new spectroscopic techniques for triggering, tracing and controlling electronic and nuclear dynamics in a broad range of systems, including atoms, small and medium-sized molecules, biological macromolecules (proteins), and semiconductor nanostructures. Long-term objectives of ADLIS include v Phase-controlled few-cycle (sub-10fs) terawatt laser pulses. Intense few-cycle THz pulses. Nonlinear THz spectroscopy with femtosecond resolution. Tracing ultrafast dynamics in molecules and semiconductor structures. Exploring and pushing the limits of ultrafast electronics. Tracing and controlling wave-packet dynamics in polyatomic molecules. Controlled generation and measurement of sub-fs XUV/X-ray pulses. Attosecond metrology. THz-pump/X-ray-probe spectroscopy of structural dynamics. Novel ultrafast-laser-based techniques for medical diagnosis.