ALPS'17 Naoya Hirota

2017-01-18 2022-09-24 miyahara

Research

ALPS'17 Report

Dates April 18 - 21, 2017 Venue Pacifico Yokohama

Naoya Hirota, 2nd year master's student

Outline of the Conference

The ALPS (The 6th Advanced Lasers and Photon Sources) was held at Pacifico Yokohama from April 18 to 21, 2017. OPIC is the only international conference on optics held in Japan, which gathers cutting-edge research and development on optics and laser technologies in academia and industry. OPIC was first held in 2012 and has been held at Pacifico Yokohama every year.

2. about his/her own presentation

The presentation was titled "Growing Carbon Nanotubes on a Silica Toroid Microcavity to observe Saturable Absorption". The content of the presentation was the content of my graduation thesis plus the results of the stabilization of partial CNT growth. Although it was my first oral presentation at an international conference in the midst of my job-hunting activities, I prepared to the best of my ability and was able to finish my presentation on time, which I think was satisfactory. During the Q&A session, I was asked questions that I had not anticipated in advance, and I was not able to understand or explain the questions in detail on the spur of the moment, which I felt was difficult.

3. topic introduction

ALPS11-2 (invited) "Broadband ultrafast nonlinear photonics in nanocarbons

The presentation was on a mode-locked fiber laser utilizing the saturable absorption property of single-walled carbon nanotubes (SWCNTs). The image of the saturable absorption device used is shown in Figure 1, which closely resembles the device fabricated by Nakamura Lab. of the University of Tokyo, in which CNTs are synthesized on a fiber with a shaved surface. The fabrication process is spin-coating ⇒ CNT growth by CVD, and the CNT growth process is similar to the process of growing CNTs on toroids conducted at Maki Lab. What attracted my attention in this presentation was the measurement method of absorption properties. As shown in the experimental setup in Fig. 2, the input to the saturable absorption device is through a fiber, and the absorption property by coupling of evanescent light and CNTs can be measured without constructing a spatial system that is difficult to align, such as the Z-scan method that I had assumed. Therefore, it is expected that even the Tanabe Laboratory can easily perform the measurement once the device is fabricated. Figure 3 shows the results of absorption property measurements with different polarization, and it can be seen that there is a large polarization dependence in the absorption property of CNTs. This means that the SA of CNTs can be tuned widely by simply changing the polarization, and by utilizing the tuning range, CW light, mode-locked pulses, Q-switched pulses, and Q-switched mode-locked pulses were generated with a single device.