Every year, the IAP scientists discuss their recent research results at the world largest photonics conference. And every time they return successfully from San Francisco - just as the three doctoral students Helena Kämmer, Sven Breitkopf and Thomas Gottschall this year.

Mrs. Kämmer won the third prize for the "Best Student Presentation" at the sub-conference SPIE LASE Frontiers during the Ultrafast Optics conference. Her lecture "Analysis of the hole shape evolution in fs-pulse percussion drilling with bursts" concern the quality and reproducibility of deep holes in the range of 200 μm up to 800 μm. Despite identical parameters, different effects - like bending or multiple endings - can occur statistically in laser percussion drilling with ultrashort pulses. Thus, the drilling process is not sufficiently reproducible and the hole quality is not optimal. In order to improve the process, the PhD student used the so-called bursts for processing instead of multiple high-energy pulses.Therefore, pulses are split into several sub-pulses.

In the research group, led by Prof. Stefan Nolte, she studied the behavior of silicon during the drilling process of deep holes with and without bursts. As a result, it was found that the time interval of the sub-pulses has a decisive influence on the achievable hole depth, quality, as well as the reproducibility compared to processing without burst.

The other two winners are working in the group of Prof. Jens Limpert, which deals with the development of lasers. In the lecture "Investigation of a non-steady state cavity for pulse energy enhancement of ultrafast fiber lasers" Mr. Breitkopf focused on a significant increase of pulse energy the usage of a passive enhancement cavity. Thus, in future high pulse energies may be produced with compact, high repetition rate laser systems, which was previously only possible with slow, very complex setups. Therefrom a large number of applications would benefit from such an approach. Mr. Breitkopf's contribution was awarded the third prize for the best student presentation in the fiber laser session of the conference.

His colleague Thomas Gottschall brought the "Jenlab Young Investigator Award" for the first time to Germany. On the sub-conference "BIOS - multiphoton microscopy in the Biomedical Sciences XVI" under the title "Four-wave mixing based light source for real-world biomedical applications of coherent Raman microscopy" he presented a laser source, which he has designed and developed during the course of his doctoral thesis. It supplants bulky and complicated laser systems with a laser source made solely from fiber optical components. It is just as small as a shoebox - and therefore roughly 20 times more compact than comparable systems. The laser is developed for an imaging technique called coherent Raman microscopy and robust enough to work in a medical setting. The goal is to identify the boundary between healthy and cancerous brain tissue and therefore to ensure the complete removal of the tumor causing only minimal damage to healthy tissue. Moreover, by this technique, the operation hours would be greatly decreased as the identification could take place directly at the patient directly, avoiding cumbersome tissue removal, constantly preparation and evaluation aside the procedure.

The "Photonics West" with its various conferences is one of the world's largest trade fairs in the fields of photonics, lasers and optical technologies. They annually attracts around 20,000 visitors and scientists from around the world.

Frontiers in Ultrafast Optics-PW16
Helena Kämmer (left) after the awarding ceremony.


Prof. Dr. Jens Limpert, Prof. Dr. Stefan Nolte
Institute of Applied Physics, Friedrich Schiller University Jena
Albert-Einstein-Straße 15, 07745 Jena
Phone: 03641 / 947811, 03641 / 947820
E-Mail: ,

News from: 02.03.2016 10:15
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