There’s a peculiar grace to living alone in a cosmopolitan city. Every night as I walk back home, my eyes wander to all the lights, signs, and historic architecture. My feet tread on cobbled pebble roads, each stone creasing my foot in a different curvature. My mind takes me into coffee shops where I unwind a day’s work with food and cake before turning home to rest my body for another day of awe, diligence, and gratefulness.
It’s been one week since arriving in Austria. It’s beautiful here. Every morning, I put on my boots and carry my pack into a city I had not known. Every corner reveals a new house, new space, and centuries old intricate, towering buildings. Time expands in these moments; your very own historicity enlarging to capture the thousands of years of history embedded in the stone.
I had wanted to write this entry after my first day of work and then the second and third but I didn’t. Each version would have revealed a different acceptance and understanding of the situation. The earlier understandings struggled to come to grip with the questions of why am I even here, how did I get here, and what am I doing here.
I’m in Vienna for research at a science institute. I am surrounded by post-doctorals, professors, and PhD candidates. I am the only undergraduate here. My group is nine people large and everyone is from a different country: Germany, Austria, Italy, Iran, and Peru. In my first week, I attended two lectures on quantum communications and mechanics and participated in four more meetings involving more quantum mechanics, theory, and current research. The Institute of Science and Technology (IST) is a place where real research is happening at a graduate level rate. I was brought here to produce results. I struggled to keep up, but I am reminded of the importance of tackling challenges one step at a time. I calmed myself down that it is okay to not know everything and that if I wanted to get anywhere, I was to start with the little steps.
I spent the following four days immersed in reading a textbook, Photonic Crystals: Molding the Flow of Light. I’ve gotten through 77 pages of it and the concepts are starting to make intuitive sense. It really is all quite fascinating. I include what I learned in the science summary of this post. I will also update on what my project is entirely on when I fully understand it.
Although I’ve entered a new environment, I haven’t felt the need to be with others in the sense that I have a lot of things I need to figure out and do including building up a strong understanding of my project, figuring out how to live in a European country, understanding cultural differences, and how to wash my laundry. The last item on the list being one I direly need to figure out fast!
Living in Austria is really different from living in America. Everything is closed on Sunday! That includes grocery stores, retail shops, and supermarkets. Only a select few restaurants and coffee shops open their doors. There is a huge culture of relaxation and rest here. After work, it is common for coworkers to drink several beers. I recently went to the Naschtmarkt, a long strip of small restaurants, at night and the place was filled with people drinking beer and having conversations. You can even find Austrians drinking on the streets, on the subway, and just about anywhere you can imagine. Some things I found funny is that people say “Super!” and “Come on.” a lot. Also the fire extinguishers are enormous! They are about three times the size of our extinguishers in the States.
Otherwise life here is really like life back home. People go to work and go home. People are people no matter where you go.
On Friday night, Alfredo, the Peruvian PhD student in my group, took me and another labmate out to a night bar. This was my first time in a bar in my life! As I don’t drink, I had some difficulty navigating bar etiquette. At one point, I ran out of water from my water bottle so I went up to the bartender and asked for water. She interpreted what I said as vodka and she proceeded to ask if I wanted a shot, gesturing a small cup in her hand. At midnight I turned 21, my birthday the 20th May which coincidentally straddled with the time of my entrance and exit of the bar. That night, I had fascinating conversations on morals, responsibility, women, and the power of science in solving God questions; those unanswerable questions.
I also didn’t know where to include this, but there were two teenagers we encountered on the way home! They asked me how old I was, and I responded 21. It seems like I will have to get used to saying that.
A short summary of the science I’ve been learning:
Photonic crystals are just about the coolest things ever. Here’s why. One property heavily used in physics is reflectivity. An example is the classic mirror. In laser systems, we trap photons between two mirrors, whereby a photon of light bounces between the mirrors indefinitely. This is called a cavity, a place where light is trapped. It turns out you can create a cavity without the use of physical mirrors but instead using only a slab of a photonic crystal such as silicon arranged in a certain geometry. Sending light into this slab then traps the light, bouncing it inside the crystal indefinitely. An example of a device that is able to do this is pictured in Figure 1.
To understand how we can trap light without using mirrors, we need to dig deep into Maxwell’s equations (shown in Figure 2) which describes light as an electromagnetic wave. Essentially light has both an electric and magnetic field. After manipulating Maxwell’s equations, we obtain the infamous master equation as shown in Figure 3. This equation turns out to be an eigenvalue equation (a common math problem in linear algebra) and by solving it we are able to obtain the allowed modes of light that can be trapped in our silicon slab. These modes describe the electric and magnetic fields of the light propagating in a certain material such as silicon. Using physics simulation software such as Comsol, we are able to model specific geometries and produce band diagrams that look like Figure 4. What we see in these band diagrams is that there is a gap of frequencies where light can’t exist, essentially allowing us to then confine light, creating a cavity.
My project is designing a high quality geometry that is able to confine light without too many losses due to leaking and reflections. To do so I need to learn Comsol. I will also have to port this into MATLab and write code. If I work hard enough we can then start fabricating these resonators and analyze them by the end of summer.
The question boils down to why do we want these tiny cavity systems in a slab of silicon? The answer is that these devices might just hold the future to our communications systems. Until next time!