CLEO Europe 2015 Tomohiro Tetsumoto
Research
CLEO Europe Participation Report
Tomohiro Tetsumoto, 1st year Ph.
in Prague, Czech Republic, 06-09 July, 2015
1. Impression of the conference as a whole
This was my first time to attend CLEO. I felt that the scale and quality of the presentations were higher than other conferences I attended (the APS March meeting was also large in terms of overall scale), but I was saddened by the rather small number of presentations by major research groups related to micro-optical resonators. I think that the CLEO in San Jose is the most valuable conference. There were a surprisingly large number of presentations by the University of Southampton in the UK.
I felt that there has been an increase in research involving plasmons as a field of presentation, and there is a strong theory that progress in FIB fabrication technology is behind this increase. Plasmons have a rather high barrier to entry in terms of fabrication, so if you want to follow the research trend, you should make a move as soon as possible. Personally, I am interested in metamaterials made of dielectric materials, and I think that the basis of the structure can be created via IME, and I would like to do some new research on silicon processes.
Another point that caught my attention was the presentation system. I thought the system was interesting and excellent, as it allowed presenters to download slides via the network and view ongoing presentations on a display installed at the entrance of the venue. However, there were some points that required attention, such as the loss of all slides inserted as auxiliary slides and the unavailability of the presenter's tool.
2. About your own presentation
The presentation itself was completed within the time limit without any problems. However, there was only one question from the chair, so it was not so satisfactory that the audience was interested in the presentation. As expected from the fact that 3 out of 6 presenters were students of Tanabe Lab, the matching with the session might not have been good. The fact that there was another session on WGM resonators in the back of the room may have also contributed to the small number of interested spectators. I regret that I was not able to answer one question appropriately. I was more concerned about speaking in English than answering the question, and I did not understand what I was saying. I would like to improve my English speaking ability first, but I would like to try to respond calmly in the future, because I was in a hurry to answer the questions.
After the CLEO, we visited the Finley group at the Technical University of Munich, which is developing research using quantum dots and photonic crystal resonators. We had a very fruitful discussion about their research. The research facilities were well finished, and I felt the importance of building experimental apparatuses so that they do not need to be moved as much as possible. In the Tanabe Laboratory, I felt the need to reconfigure the alignment system so that each experiment can have its own measurement system, although it is necessary to devise a way to do so due to space limitations.
3. Topic Introduction
interpoint (interword separation)A Highly Efficient Nonlinear Platform: AlGaAs-On-Insulator
Presentation by the group of Technical University of Denmark.
A report is given on the world's lowest power optical Kerr comb generation using a 5 mW pump light in a ring resonator fabricated in AlGaAs. According to the original manuscript, a highly efficient idler light was generated by four-wave mixing generation using an AlGaAs waveguide (only 8.7 dB intensity drop from the signal), so the ring-based comb generation seems to be a recent achievement.
AlGaAs has high nonlinearity in the telecommunication band, a wide band gap to avoid two-photon absorption, and a refractive index that can be changed depending on the Al content (n The material has been considered to be advantageous for nonlinear applications because of its properties (= 1.42~2.02). On the other hand, it has the disadvantage of being difficult to process, and has not been used in many applications.
Since the group seems to have solved the process problem, AlGaAs may become the new platform for nonlinear applications and optical Kerr comb generation.
interpoint (interword separation)Quantum Information Processing Using Active Silicon Photonic Integrated Circuits
As the title says "quantum," this research is aimed at quantum signal communication. It was shown by calculation and experiment that programmable integrated optical circuits with high fidelity can be fabricated by combining MZI interference with silicon.
The circuit itself combined with MZI interferometry has been proposed in the past (M. Reck, et al. , PRL 73, 58-61 (1994)), and the design guideline is based on it. I think that the quantum background is based on the fact that a 2 x 2 splitter (e.g., 0.5:0.5) can create a single photon superposition state, but I am not sure how the overall optical circuit will differ from a simple splitter from a macroscopic point of view. Will there be any difference in the configuration of the logic circuit? (There is an introduction of CNOT and CPHASE gate)
The fact that the circuits are realized in all-silicon is attractive, and since our laboratory has a strong interest in large-scale integrated circuits using IMEs, it may be necessary to check out some of this research.
Reference: A. Politi, et al. Science 320, 646-649 (2008). arXiv 1406.3255 (2014).
interpoint (interword separation)Reconfigurable metasurface driven by MEMS
The metamaterial structure is moved in a MEMS-like manner to change its characteristics. Electrodes are placed on each periodic structure by wire bonding, and the precise control of each structure individually was introduced. While there have been many studies of changing the characteristics of structures by moving them mechanically as in this research, I have never seen such detailed individual control as in this case. As I plan to visit a MEMS-related laboratory in the summer, I would like to ask some questions about wire bonding technology.
interpoint (interword separation)Tunable GHz optomechanical crystals
Presentation from the Painter group. Cavity optomechanics applications require tuning of the mechanical frequency, but until now there has been no effective means of doing so. In this presentation, a method to modulate the resonance frequency of a mechanical resonator by electrically moving the structure and applying tension to the structure was introduced. An interesting aspect of the research is that it is based on phononic crystals. A phononic crystal is fabricated to localize the vibration at the center of the beam structure by creating a periodic structure that resembles rectangles of different sizes arranged in a bar. The U-shaped periodic structure surrounds both sides of the crystal to open the photonic band gap.q = 105The results of the calculation are only available.) Although only calculated results are available, the machine frequency is 5 GHz, and the frequency modulation is said to be sensitive to a force of 100 nN, with a change of about 400 KHz.
The Painter group is proposing new resonator configurations one after another, and I believe that the basis for this is computational power. I have been interested in phononic band calculation for a long time, but I have not been able to do it yet, and I would like to work on it in the near future so that we can do it in our laboratory.
interpoint (interword separation)Euler bends
A small story. While listening to a presentation on nonlinearities in waveguides, the term Euler bends came up. From the context, I guessed it was a crossoidal curve, and when I looked it up, it turned out to be right. It seems that ring resonators of Euler bends have already been studied, and the novelty of crossoidal rings was again denied.
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