[No. 194] Hiroaki Handa

Thank you very much for this valuable opportunity to contribute to the Alumni Relay Column.

I am currently working as a math teacher at a private high school called Joban High School in Gunma Prefecture. In my department, there were not many people who, like me, completed the teacher training course and actually became teachers. Furthermore, being from the Department of Electronics and Electrical Engineering (a physics-based field), I was the only one in my graduating class to become a math teacher. Therefore, my case may be unique, but I would be honored if my story could be of some help to the readers.

Although I had been interested in becoming a math teacher since high school, I wasn't confident in my mathematical abilities. I also enjoyed science experiments and had a vague interest in becoming an engineer. Therefore, under the *Gakumon* (academic discipline) system at the time, I chose *Gakumon* 1 (physics-based) instead of *Gakumon* 2 (mathematics-based). Looking back now, I believe this was a really good choice.

After actually enrolling, I struggled greatly with the difficulty and pace of the university classes. I was also taking the teacher training course, and I couldn't keep up, repeatedly failing to earn credits (though that's just an excuse...). As a result, my grades were not very good. However, even in difficult lectures where I didn't understand the fine details, I was able to find my own sense of enjoyment.

Joining a research laboratory in my fourth year has led to a connection that remains important to me to this day. In Professor Toshiharu Saiki's laboratory, research was conducted in three teams. Among them, I chose the "Femto team," which conducted experiments using a femtosecond pulsed laser, because I wanted the chance to use expensive equipment. The "Femto team" was a small group consisting of just myself and a kind second-year master's student, so we were always communicating and conducting experiments together. Our research involved irradiating a two-layer structure of two different phase-change materials with lasers from both sides at different times, and we were searching for conditions that would cause a change in the time difference of the irradiation from both sides. The work was mainly experimental, with occasional calculations using FDTD simulations. In addition to the research itself, I was not good at standing in front of people, so my senior watched me practice my presentations many times, and I was able to successfully complete both my presentation and thesis.

During my time in the lab, I of course conducted research, but I also fully enjoyed? myself by letting loose at summer camps, ski trips, and drinking parties.

Afterward, through a fortunate connection, I began working at my current workplace, Joban High School. Joban High School is divided into a Special University Preparatory Course, a University Preparatory Course, a General Course, and a Physical Education Course. Each course has its own unique characteristics, and the students have diverse personalities. To help the students grow, I engage with each one of them individually, focusing not only on their academic studies but also on broader aspects of their lives. The students I had been in charge of as a homeroom teacher since their first year have just graduated. Having watched their growth up close, my joy is immense. I hope to maintain some form of connection with them in the future.

Each course has various initiatives, and one of them is the "Keio University Visit" for students in the science track of the Special University Preparatory Course. Our school has a connection with Keio University, as our vice principal is a graduate of the Department of Chemistry, and several other staff members are also graduates of Keio University, including from the Faculty of Science and Technology. This connection allows our students to visit the Yagami Campus and its research laboratories. Since I started working here, Professor Saiki has kindly agreed to let our students visit his lab as well. It was memorable to see the students' eyes sparkle with excitement, even as they were overwhelmed by the university atmosphere. I am also very happy to be able to maintain a connection with my research lab even after graduating.

It is probably rare for someone who graduated from a physics-based department to become a math teacher. I chose my current profession because I find more enjoyment in using mathematics to think rather than in pursuing mathematics itself, and I wanted to convey that to the next generation. Life is a path where there is no single right answer, and so, in my still-youthful opinion, I believe that having your own will and intentions can make it more enjoyable.

Furthermore, because my job involves interacting with people, I truly feel the importance of human connections. Before working at Joban High School, I didn't know that the school had a connection with Keio University, nor did I ever imagine that I would be able to maintain a relationship with Professor Saiki and my former lab. You never know where connections will be made, which is why I believe it's important to cherish every encounter.