Sven Teichmann''s doctorate features experimental work on a high-harmonic generation source and coherent diffractive imaging. High-harmonic generation allows generating coherent and laser-like extreme- ultraviolet and soft x-ray radiation based on the frequency-upconversion of laser light. A novel and successful approach of employing harmonic emission that consists of multiple harmonic orders is presented. This emission is utilized for coherent diffractive imaging by illuminating a sample of unknown structure, e.g. a membrane protein. The diffractive image of that sample is then processed by means of computational algorithms and the structure of the sample can be recovered. This innovative work of a very high level of technical achievement is considered as internationally significant by world leaders in the field of high- harmonic generation and may prove valuable particularly for time-resolved spectroscopy, sources of soft x-ray and extreme-ultraviolet radiation, and imaging based on harmonic emission.