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WHAT EXACTLY HAPPENS WHEN LASER ENERGY IS DEPOSITED IN GLASS?

Fundamental understanding of the interaction of ultrashort laser pulses with glasses

Glass plays an outstanding part in numerous applications in optics and photonics, both in research and in everyday life. Glass properties are specifically adapted to the task being performed, but this also necessitates the development of innovative processing methods.
A prominent example is tempered glass, which is used for displays due to its high scratch and crash resistance. However, processing the chemically strained display glass is a challenge, since conventional processing methods generate stresses or microcracks.
Alternatively, ultrashort laser pulses can be used to make targeted modifications to the volume of the glass in order to enable defined cutting of the workpiece without affecting the surface. This requires a profound understanding of the process to optimize the highly nonlinear interaction process. Klaus Bergner addressed this issue during his doctorate and developed non-contact measurement concepts and methods.
Using a modified time-resolved microscope setup, he characterized the energy deposition with high temporal and spatial resolution and followed the subsequent relaxation processes experimentally. Mr. Bergner was able to prove that there is a significantly different dynamic interaction than previously assumed by experts: the pulse duration has a significant influence not only on the process initiation and the interaction volume, but also on the achievable electron densities.
Mr. Bergner used the knowledge gained to separate gorilla glass (Corning) exemplary. In addition to spatial beam shaping, he also used temporal beam shaping by breaking down the pulse into individual subpulses (so-called bursts). Thus he succeeded in separating the glasses in a defined way. He achieved surface roughnesses well below 1 µm. Another result of his work is the structuring of glasses up to a thickness of 2.5 cm, which is a world record at a processing speed of 100 mm/s. In addition, Klaus Bergner improved the time-resolved tomography in the fs range using a spatial light modulator. This technology still has far-reaching applications beyond glass applications.

2019-11-28_Bergner Werth Preis
Dr.-Ing. Siegfried Werth Foundation awarded Dr. Klaus Bergner the Dr.-Ing. Siegfried Werth Prize 2019 in the field of non-contact, dimensional measurement technology.
fltr: Dr. Falk Eilenberger (IAP), Dr. Klaus Bergner (Alumni IAP), Arno Fink (Chairman of the Werth Foundation), Dr. Ralf Christoph (Managing Partner of Werth Messtechnik GmbH). [rights: Anne Kirch]


Dr. Bergner has successfully generated a fundamental understanding of the interaction of ultrashort laser pulses with glasses by means of microscopic investigations of the highest time resolution. Through its application orientation, it bridges the gap between physics, engineering sciences and glass sciences. This mixture of basic research and application also impressed the Dr.-Ing. Siegfried Werth Foundation. In recognition of the experimental and theoretical complexity, Dr. Bergner was awarded the Dr.-Ing. Siegfried Werth Prize 2019 in the field of non-contact, dimensional measurement technology.


News from: 10.12.2019 10:52
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