Your area of expertise is semiconductor nanostructures and quantum dots. What are the most significant studies in that field right now?
The most “famous” semiconductor today is probably silicon. Research is being done into finding ways to make silicon chips and circuits for real-life application. One other popular subject of study is light emissions, which can also be produced with the use of so-called III-V semiconductors. Every day people encounter devices that employ light emission, but they likely don’t concern themselves with its nature: among them are LED-TV’s, car headlights and traffic lights. The Internet wouldn’t have been possible without light-emitting semiconductor devices. The most modern studies right now are concerned with producing light emissions from single photons using semiconductors. I, among other things, am working on this task. It’s important to keep in mind that, when we’re dealing with several photons, the physical laws are different from what they’d be if you were to work with a beam made of millions of photons. In a system where photons are “released” one by one, the quantum properties of light are manifested. We use quantum dots to achieve light emission by single photons. A quantum dot is a miniscule object made up of 10,000-100,000 atoms that emits these photons.
Why do we need to “disassemble” light into photons?
First and foremost, this is important for the development of quantum computers, as well as communication and cryptography. These are areas that could greatly benefit us in the future, especially in case of the latter. You will instantly know if someone’s trying to intercept your data if you’re transmitting it using single photons. Quantum computers are in the long-term perspective and they’ll only start being used in 10 or even 20 years. But they’ll possess processing power impossible for modern computers, which is why large companies like Google or Microsoft are investing heavily into their development. In this context my work is important, as we want to use solid-state systems for quantum applications and create quantum microchips using III-V semiconductors. In addition, the future quantum computers will be compact unlike the first computing machines that used to take up a whole room.
Why does it take so long to develop a quantum computer? Is it difficult to make photons interact with each other?
Yes, the difficulties are mostly science-related and yes, photons indeed don’t interact with each other, but we’re working with quantum dots that emit them. And the dots can, in fact, interact between themselves. There are two technological challenges. The first is that this generation of computers will require the creation of many elements capable of managing a large number of qubits (in modern quantum computational schemes the maximum number of qubits working at the same time is approximately 16). The second is that quantum state is extremely fragile and is affected greatly by environmental factors. For that reason, we need to somehow isolate our qubits so that they remain unaffected. Scientists have already recognized ways of solving these issues, but they are highly difficult and resource-consuming and will likely take years.
Credit: prointech.ru
You are the co-director of the research on hybrid light-matter states in low-dimensional quantum materials that is being conducted at ITMO University using a megagrant (a large research grant awarded by Ministry of Education and Science). Will the results of this work have fundamental influence on the methods of “manipulating” light?
We’ll be using the megagrant to facilitate the research into semiconductors and a new atom-thick material the properties of which would allow to effectively manipulate light in waveguides. We’ll study ways to strengthen the interaction between light and matter as well as to create hybrid light-matter states, polaritons, which, unlike photons, can interact with each other as massive particles. The effectiveness of their interaction is very high and therefore only very low light levels are required to achieve the desired interactions. The megagrant will also allow us to found an international laboratory for semiconductor research.
What are the possible applications of hybrid light-matter states?
Firstly, we’ll be able to create a polariton laser, which will be much more effective than a regular device. This laser can be used for optical data transmission. Secondly, there is a lot of promise for solitons as information carriers. The chief property of solitons is that these electromagnetic waves don’t dissipate in all directions, but are instead very localized and directional. For that reason there is very little loss of power and therefore they can deliver information unchanged. In addition, it’s important that the optical signal is launched through the waveguide in such a way that it is detected in a predetermined spot and not at random. This is possible thanks to solitons. We’ll be trying to create polariton systems and schemes where data is transmitted by solitons.
Gravitational waves. Credit: svopi.ru
On a global scope, which scientific events could drastically change our life?
In the last few years what has really inspired and awed me is the discovery of gravitational waves. Sure, it impressed everyone, but for me this discovery had a special meaning. It showed the importance of long-term research. Gravitational waves have been predicted 100 years ago. There was an understanding of what they are and how they can be found, but it required a lot of intellectual and financial efforts to finally achieve that spectacular result. The discovery of gravitational waves is a lengthy story of technological development, including the various photon detection technologies, which would be impossible without lasers and semiconductors. It is examples like these that politicians need to be shown if we want them to understand the importance of science and scientific progress. The majority of people also understand the meaning of this discovery, of how exactly it was made and how exciting it is.
Nowadays we hear a lot of talks about “technological literacy” and how it’s shameful not to have interest in science. But people often have a hard time understanding things like nanophotonics or metamaterials…
That’s how it is everywhere, and it’s quite natural. Sometimes we poll students and ask them which scientific fields they’re most interested in. They tend to choose astronomy, high energy physics or particle physics. If you tell them they could study lasers they say sure, it’s interesting, but astronomy is more interesting. Quantum computers are however popular, too and most certainly catch the attention of students and the public in general. We’ve recently started a Quantum Optics course for bachelors in my university and it’s been very popular. Had we offered just lasers to the same students, not many of them would have signed up for the course. The thing is that quantum technologies are technologies of the future and they will change a good deal of our everyday life. And that’s a lesson to every scientist: one must strive to study the things that have the potential to have an impact on society. Robotics is also very relevant today and there’s a lot being invested in it because it will also have a great effect on our future way of life.
Science communication, too, plays an important role in that, otherwise how would society learn about future breakthroughs?
Absolutely. I don’t know how it is in Russia, but in the UK when scientists apply for a grant, they must fill in a field that asks them to describe how the community will be involved in the research. There are young employees in my university who make popular-science videos for YouTube that are accessible to those with minimal scientific knowledge. We also present our projects at expositions and make the expositions available to schoolchildren. Ultimately, it is important that any scientist, any university can make the concept of research understandable for society and potential investors. Only then people will believe and invest in it.
