In 2007, the New York Times named Marin Soljačić as the author of one of that year’s top 70 “curious, inspired, and perplexing” inventions. The celebrated scientist, winner of numerous awards, and MIT professor is known to the world as, first and foremost, a researcher of wireless energy transfer technology. His experiments and studies on the subject are often compared to those of Nicola Tesla. In recent years, Prof. Soljačić has been exploring the applications of photonic crystals in solar energy production and the usage of machine learning algorithms in photonics. He presented a report on his latest research during the METANANO conference, which has recently concluded in St. Petersburg. In this interview with ITMO.NEWS, Marin Soljačić discusses the effects of the latest tech on research and explains why scientists must not limit themselves to a single field of study.
You are well-known for your electromagnetism research. But there is another topic you’ve been exploring in recent years, and it is that of photonic crystals. What makes these materials so interesting to scientists?
From the perspective of physics, there exists a close similarity between the propagation of photons in photonic crystals and the movement of electrons in semiconductors. In other words, many phenomena typical to electrons in semiconductors have a close analog in photons and photonic crystals. That is very evident in topological physics. Many of the topological phenomena that have been a hot topic in the electronic community have actually also been predicted and discovered for photons in photonic crystals. Today, people treat photonic crystals with substantial optimism because these materials have a variety of possible practical applications in photonics.
You’ve also been looking for ways to apply photonic crystals in solar power technology. What can you tell us about your research in this field?
There is a great deal of interest in using photonic crystals to enhance the efficiency of commercial photovoltaic solar cells. But, there are other approaches for converting solar energy. For example, when you heat things up, they begin to radiate energy. Depending on the type of a photonic crystal, it might be radiated at different frequencies. From an energy conversion point of view, this effect can be beneficial in a variety of situations.
One such application is in the solar thermophotovoltaic cells. We use sunlight to heat things up to a rather high temperature. Then, when the object begins to radiate energy, that radiation can be converted to electricity thanks to photovoltaics. All this is possible because photonic crystals allow us to control the emission spectra, which is useful for the purposes of optimizing and enhancing the efficiency of such systems.
(Read more about this research project here; the research paper has been published in Nature Energy – Ed.)
What are, in your opinion, the most promising applications of photonic crystals? Can we say that they’re already being used today?
One practical application of the crystals is in the development of photonic-crystal optic fibers, which are used today in surgery. Then there are photonic-crystal surface-emitting lasers. Professor Susumu Noda from Japan is one of the pioneers of that field. Lasers of that kind have plenty of fascinating additional properties, such as the high power and control over the beam, as well as others. There are other applications, too, which we may see in practice quite soon.