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Dissertation
Optimierung von Nanostrukturen in Dielektrika für biomedizinische und technische Applikationen durch zeitlich geformte Femtosekunden-Laserpulse
(2017-09-28)
Das Ablationsverhalten von Dielektrika wird in Abhängigkeit von unterschiedlich zeitlich geformten Femtosekunden-Laserpulsen analysiert. Dabei entstehen unterschiedlich tiefe Strukturen im Nano- und Mikrometerbereich. In zwei Anwendungsbeispielen wird deren Anwendbarkeit für biomedizinische und technische Applikationen beschrieben.
Dissertation
Laser amplification in excited dielectrics
(2018-02-12)
Today, laser processing of dielectric materials with ultrashort, femtosecond laser pulses finds a great variety of applications. While ablation, cutting or welding of different types of glasses are widespread and popular examples, nanostructuring of transparent crystals or optoporating cells is part of more recent scientific studies. Although the material systems seem to be very different, their interaction with visible and infrared wavelengths is very similar: the light is simply transmitted. This changes drastically ...
Dissertation
Methods of generating carrier-envelope-phase stabilized, intense, few-cycle laser pulses
(2015-02-12)
Ultrafast laser pulses have become an integral part of the toolbox of countless laboratories doing physics, chemistry, and biological research. The work presented here is motivated by a section in the ever-growing, interdisciplinary research towards understanding the fundamental workings of light-matter interactions. Specifically, attosecond pulses can be useful tools to obtain the desired insight. However access to, and the utility of, such pulses is dependent on the generation of intense, few-cycle, carrier-envelope-phase ...
Dissertation
Efficient Characterisation and Optimal Control of Open Quantum Systems - Mathematical Foundations and Physical Applications
(2015-06-19)
Since no physical system can ever be completely isolated from its environment, the study of open quantum systems is pivotal to reliably and accurately control complex quantum systems. In practice, reliability of the control field needs to be confirmed via certification of the target evolution while accuracy requires the derivation of high-fidelity control schemes in the presence of decoherence.
In the first part of this thesis an algebraic framework is presented that allows to determine the minimal requirements on ...
Dissertation
Optimizing Robust Quantum Gates in Open Quantum Systems
(2015-05-27)
We are currently at the cusp of a revolution in quantum technology that relies not just on the passive use of quantum effects, but on their active control. At the forefront of this revolution is the implementation of a quantum computer. Encoding information in quantum states as “qubits” allows to use entanglement and quantum superposition to perform calculations that are infeasible on classical computers. The fundamental challenge in the realization of quantum computers is to avoid decoherence – the loss of quantum ...
Dissertation
Theory of laser-induced ultrafast structural changes in solids
(2010-04-21)
The present thesis is a contribution to the study of laser-solid interaction.
Despite the numerous applications resulting from the recent use of laser technology, there is still a lack of satisfactory answers to theoretical questions regarding the mechanism leading to the structural changes induced by femtosecond lasers in materials.
We provide here theoretical approaches for the description of the structural response of different solids (cerium, samarium sulfide, bismuth and germanium) to femtosecond laser ...