The Laser Zentrum Hannover e.V. (LZH) is one of the leading institutions in applied laser research. With about 250 employees, basic research, applied research, and industrial developments are realized. The Department of Optical Components offers a master thesis on the following topic for the next possible date:
Model-based qualification of measurement methods for
laser-induced damage threshold of optical components
Fields of Study: Physics, Optical Technologies
Problem:
Since the beginning of high-power laser technology, it has always been the optical components that limit the achievable level of output powers. While more than 50 years ago, it was inclusions that literally exploded in the laser glasses under the influence of intense laser radiation and destroyed the material. Nowadays, hardly visible defects on the nanometer scale in the optical coatings limit the laser-induced destruction threshold of the optics according to almost the same principle.
After more than five decades of intensive research activities on a hardly manageable variety of further destruction phenomena, one central question still remains incompletely solved in the community:
How do we determine a laser-induced destruction threshold with high reproducibility and comparability?
An outstanding problem here is the diversity of the acting destruction mechanisms, requiring specific measurement methods. In the course of international efforts and standardization, it has now been possible to identify suitable measurement methods for the destruction threshold. While some measurement principles have already been proven in practice, a qualification especially for the characterization of components with defect-induced destruction, which are frequently used in laser technology, is still pending. The topic of the master thesis is to start precisely at this point: it is intended to simulate the defect-induced destruction mechanisms based on models known from the literature and subsequently implement measurement routines according to the current state of international research. In this way, many measurements can be carried out virtually on the computer without the extremely high effort otherwise required in experiments. Significant findings are expected on the statistical nature of the tested measurement concepts and on their suitability for international standardization. This master thesis, which is initially purely theoretical and oriented towards program development, can still be supplemented in the practical area by selected comparative destruction threshold experiments.
What can we offer you?
Calculated defect-induced field elevations in an interference layer system (left) and scattered light mapping for defect identification in optical components (right).
The characterization group is concerned with the highly sensitive determination of the optical properties of, among other things, laser optics for LIDAR-based earth observation systems, complex filter systems for astronomy, and polarization and beam shaping components for laser materials processing. The measurement methods developed in the working group represent the international state of the art in technology and science and are used worldwide both in industrial series production and in research and development. The working group is currently in charge of the corresponding international standardization project ISO 21254. Implementation of the knowledge gained can be achieved in a targeted manner in this constellation.
What do you need to bring with you?
The offer is aimed at physics and optical technologies students who enjoy developing computer programs with a relevant physics background. A start with an internship phase according to the respective study regulations can be arranged.
Severely handicapped persons are given preference in case of equal aptitude.
The LZH attaches great importance to professional gender equality.
PLease send your application to:
Laser Zentrum Hannover e.V.
Dr. Andreas Wienke
Abteilungsleiter Optische Komponenten
Hollerithallee 8
30419 Hannover
Tel.: 0511-2788-261
E-Mail: a.wienke@lzh.de
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