CLEO-EU 참가 보고
6월 26일 - 6월 30일, 독일 뮌헨 국제회의센터 메쎄 뮌헨, 뮌헨, 독일
修士課程2年 Lemcke Deniz
So basically, since we travelled to Munich, it was only natural that we also had a lot of beer. Despite our cultural assimilation we attended the conference. My poster presentation was great and led me to gain a lot of insights and learn a tremendous amount from researchers who are more experienced than I am.
We arrived in Munich around 9 am local time, but it took quite a while for the others to get through the passport control. That’s why it was already noon when we got to the central station. A currywurst and a visit at the castle Residenz München later, we checked into the hotel and made it almost on time to the first plenary talk of the conference. Professor Donna Strickland gave us a brief introduction to her time as a PhD student and what lessons she learned while she developed chirped pulse amplification. Her and her supervisor's research about that topic got awarded by the Nobel Prize in Physics 2018. One takeaway from her talk was that one should never rely on what one could possibly get but rather work with what one gets. In that regard, reality is often disappointing, since production errors and other factors have an enormous impact on the cavity. As for her, she wanted to use an advanced fiber, but when it was delivered, she had to find out that it was shorter than expected. Despite problems like above she is proof that it is still possible to produce Nobel-winning research. It seemed like a tip for future researchers that adaptability is one of the important traits one should have.
3. Poster Presentation
After another plenary talk on Tuesday, we went straight to our poster presentations. During the poster session I got to meet new people and learned through their questions and doubts. Professor Argyris who worked over a decade with chaos synchronization had a few suggestions and a quite fundamental doubt. In his research he calculated quite often the Lyapunov-exponent and the actual entropy. So, he naturally asked me whether I did it too, but I didn’t even know one could calculate the entropy of that system. As for his doubt, he said he never tried synchronizing the chaos in microresonators, because he considers the non-linearities in the resonators as too small. With small non-linearities a synchronization might be easier, since the chaos might not be chaotic enough, meaning it couldn’t be used for secure communication. Professor Argyris’ valuable point of view let me help broaden my understanding in that field. Furthermore, the questions from other graduate students, PhD candidates or post docs also helped me further strengthen the explain-ability of my research topic.
4. Interesting Plenary Talk
The last plenary talk I attended was a joint presentation given by Tammy Ma and Constantin Haefner. Their talk introduced the idea of laser-driven inertial confinement to enable fusion energy. Until then I was not aware that there is a third method to achieve fusion reactions, with the sun being an example for gravitational confinement and the ITER and tomahawk power plants being an example for magnetic confinement. What they did was build an enormous laser and focus the entirety of the beam or rather beams onto a cube with a volume of a few cubic millimeters. Miss Ma said that their used laser, called NIF, is the largest laser in the world on an area of 3 football fields. Unfortunately, I don’t know how big a football field is, but the laser might be relatively big, since it incorporates 192 beams in total and is able to shoot a pulse with 2 MJ or 500 TW and a pulse length of 25 ns. To generate the 192 beams, they start with two lasers which start the first beams. Those beams are then alternatingly split and amplified on those three football fields. In the end all the beams are focused on to a small volume of a Deuterium/Tritium mixture where the fusion should take place. After a multi-decadal endeavor, they could finally announce that they achieved ignition, meaning the fusion of Deuterium and Tritium. By only putting in 2.05 MJ they generated 3.15 MJ of fusion power. Although this is already a noteworthy achievement, using inertial confinement fusion for energy production is still far away, since they are only able to shoot the laser once every 4-6 hours and the output/input energy ratio is too low to make it economically practical. However, there are roadmaps published by other scientists telling what must be done for fusion energy to be achieved and it seems possible to reach a level for inertial confinement fusion to use it as an energy source next to other regenerative sources in the future.
5. Gaining Inspiration from Experts
After that I joined a session on ultrafast physics in condensed matter. Claus Ropers from Max Planck Institute for Multidisciplinary Sciences gave a tutorial on Quantum-coherent Electron-Light Interactions in Electron Microscopy. The way he presented and seamlessly knew everything about his research field, citing relevant papers by heart to give examples, was very inspiring. He works on ultra-fast transmission electron microscopy (UTEM) where one uses photons to trigger the emission of electrons. These fast electrons will interact with optical near fields, so that they lose a whole number of photon energies depending on the frequency of that electron. With that he explained further what a quantum walk is and how the relative spectral density can be used to measure the exact phase of the electron wave. But what I found interesting in his talk was a paper of his group which he briefly introduced where they used a microringresonator to modulate the phase of an electron beam. They merged integrated photonics with electron microscopy.
6. Example of Cultural Differences
Speaking of microringresonators, what we mainly do is generating optical frequency combs in those resonators. To see more applications for optical frequency combs, I went to Professor Minoshima’s tutorial on “Optical frequency comb applications beyond frequency metrology using versatile control of optical waves''. However, that tutorial was stuffed with information that I couldn’t get everything. But topics included all-optical signal processing and calculation via Hilbert transformations and using dual-comb-spectroscopy in optical network analyzers or in single photon measurements.Right after professor Minoshima, a PhD student from Great Britain presented, I couldn’t fail to notice the significant difference between western style presentations and eastern style presentations. While the Asian style presentations tend to have a lot of figures, text and colors on each slide, the European or American slides seem to be more minimalistic. He put only one figure per slide with a title.
On Thursday afternoon we decided to travel to Chiemsee one hour away from Munich. It is not only a picturesque lake with two islands, but has played a role in German history, too. In August 1948 on one of the islands at former Herrenchiemsee Abbey was the constitutional convention held which contributed to the process of drafting and adopting the contemporary German constitution, the Basic law. We also wanted to try out the beer called Chiemseer which is brewed near Chiemsee, but ironically, we could not find it. Instead, there was a small brewery on the second of Chiemsee’s islands which sold the there made “Inselbräu” or directly translated the “island-brew”. That beer was quite something, it’s floral and fruity notes really complemented the hoppy flavour.
8. Laboratory Tour
Friday, we were invited to a laboratory tour at the research center Garching. We met with Professor Johnathan Finley, the head of Walter Schottky Institute – Center for Nanotechnology and Nanomaterials (WSI). After he gave us an introduction to his institute and what they are overall doing, his group leaders led us through three of their laboratories. The WSI laboratories looked around hundred times tidier than our laboratories at Keio, although they said it would be messy, since they were cleaning on that day. They are also very well equipped, probably because they share their equipment with other institutes.