Interview: Dr Arseniy Kuznetsov, senior scientist, A*Star
Image credit: Nick Smith
One of the world’s leading pioneers in nanophotonics, Dr Arseniy Kuznetsov, a recipient of the IET’s Harvey Engineering Research Prize, discusses his work in dielectric nanoantennas and how it can be applied in areas ranging from medical diagnosis to improving our smartphones.
The past few decades have seen numerous attempts to bring 3D animation to computers and consumer devices, but results have been far from successful. Even though 3D TVs made it to market several years ago and events such as the Olympics and the World Cup were captured in stereo, it did not take long for manufacturers to realise these products were not going to drive sales. Having to use special glasses to see stereo images did not help either. What we really want is an image that conveys depth properly, through holographics.
According to Arseniy Kuznetsov, a photonics expert and pioneer in the development of nanoantennas, a display that brings holographics to smartphones is on its way. “People have been dreaming about this and talking about it for a long time,” he says. “We know this because we see it in science-fiction movies. We have wanted to communicate in 3D rather than use a flat screen for some time now.”
We will see this within 10 years, not least because “there are already several companies that have started to look into this. I know Samsung is already investing in this, and so it follows that other companies are, too.” What this means is that, according to Kuznetsov, we will see the first prototypes within five years, with development to production “taking maybe a couple more years. When we look at the screens our eyes will get exactly the same perception as looking at a 3D object.”
“What we need now is some time to develop this technology to get moving holograms onto a real level.” The way to do that is through creation of tiny antennas that cover the surface of a 2D display; antennas so small they don’t generate photons in the RF part of the spectrum, but in the region of visible light.
“Basically, all engineers know that antennas are used to transmit radio waves,” says Kuznetsov. The size of the antenna is dependent on the wavelength at which it operates. “A radio antenna transmitting waves of one metre will be of that sort of size. Yet what if you want antennas for transmitting light? In this case, the wavelength is about a millionth of the size of radio. You need to shrink the size of the antenna down to 100nm scale. With development of nanotechnology, it has become possible to produce such devices to manipulate light on a nano scale.” That is the basics of nanophotonics: the science of manipulating light at a very small, sub-wavelength scale.
Creating nanoantennas to transmit light is only part of the problem. These nanoantennas need to steer light dynamically. “This is because what we have now are static holograms. What we need to do - and this is what the prize was given for - is to make each individual antenna ‘tunable’, to make the holograms move. Then we will experience something that will change the future of the way we receive information and view images on the screens of our electronic devices. It’s going to revolutionise the way we interact, because if you receive information in three dimensions, you simply get much more than you get from flat screen displays.”
The prize he is referring to is the IET’s £350,000 A F Harvey Engineering Research Prize, with the citation indicating that it has been made in the field of dielectric antennas. It’s not a technology on the tip of everyone’s tongues, but if Kuznetsov is right and the fruit of his labour makes its way onto our smartphones, billions of people will be using his technology, if only for blowing up 3D aliens, thanks to tuneable nanoantennas.
I spoke to Kuznetsov, who is a senior scientist at the advanced concepts and nanotechnology division at the AStar Data Storage Institute in Singapore, just before he was to deliver his prize lecture at the IET’s London headquarters, Savoy Place. Entitled ‘Novel resonant dielectric nanophotonics for novel technologies’, the presentation outlined the Russian technologist’s vision for “a new concept of low-loss dielectric nanoantennas and their implementation in real-life devices through a switchable nanoantenna approach”.
It’s not just displays. Photonics-based chips will make computers faster, while holography-based technology will become part of our everyday lives. For most end-users, what this means is that in terms of the quality of displays on our gaming devices and smartphones, nanophotonics will become quite literally a game-changer.
Commenting on how nanoantennas are poised to play a central role in the world of consumer electronics, Kuznetsov says: “I am excited to see how fast novel technologies are becoming a part of everyday life. Light, and in particular nanophotonics, is expected to be an area of major technological breakthrough in the near future”.
He says that he is “honoured to receive this award and I believe it will help me and my team to develop a technology that can make a positive impact on society”. His work at AStar means that tuneable antennas can be integrated into high-resolution augmented reality, will create 3D holographic displays for smartphones and will “significantly transform the way in which we receive and interact with information”.
This is a view supported by Sir John O’Reilly, chair of the IET’s selection committee for the prize, who commented that Kuznetsov’s research “makes science fiction become science fact by overcoming current bottlenecks and limitations in developing switchable antennas, which are likely to open doors for additional real-life applications, generating an explosive growth of nanophotonics-based products and markets”.
Kuznetsov was born in the industrial city of Nizhny Novgorod (under the Soviet administration formerly Gorky), where he completed his early education and first degree at Lobachevsky State University, “one of the 10 biggest in Russia”. Following this, he obtained a French-government-sponsored scholarship to produce his doctorate, defending variations of his thesis in both France and Russia. Today, Kuznetsov has two PhDs, the French one in process engineering and the Russian in physics. After that, he stayed in Russia for a further year, before proceeding to acquire his postdoc qualifications at the Humbolt Foundation in Germany, where he remained until 2011. He then moved AStar, whose address on Fusionopolis Way will leave no-one in any doubt that this is a science research facility.
“The goal of AStar is to work between universities and industry. We are doing academic research, but its purpose is to develop commercial technology. We do more than publish academic papers: we work on projects that are of interest to industry, specifically to develop the economy of Singapore.”
Having won the largest financial prize in the IET’s gift, Kuznetsov plans to put it to good use, by expanding AStar’s group of scientists working on nanoantennas. “We will use the prize to support research in that direction. We are hoping to recruit another scientist and will also invest in equipment”.
Kuznetsov explains how nanophotonics emerged from the now relatively mature world of plasmonics. The problem with this line of technology, he explains, is that it “got stuck when it came to transferring ideas to applications. This is because there is a lot of loss in plasmonic devices.” On top of that, metals often needed for plasmonics, such as gold and silver, are difficult to incorporate into the chipmaking-type processes used to make displays and integrated circuits.
“The approach that we developed at AStar, which we are promoting, and which many groups around the world are starting to work with, is this: instead of using the plasmonic approach for nanoantennas, we are using high-refractive dielectric and semiconductor materials to allow resonant antennas, but without loss. A similar approach exists with radio frequencies, but it’s not as popular because metals are so good for this purpose, and so dielectric didn’t really get developed quickly. But in optics, metals don’t perform as efficiently. Microelectronic-friendly materials such as silicon are much better”.
He says there are “plenty of applications for nanoantennas in bio-imaging and bio-sensing at the moment, where current technology is fluorescence, which is not so fast. Nanoantennas can be used to improve the imaging speed. This is an important direction for the technology. Another, which is used by companies such as Seagate, is to focus light to a really small scale. The reason it’s important is that when you use a lens, you cannot focus light to below the diffraction limit. Yet with nanoantennas you can focus it to a sub-wavelength scale. This is used in a new approach for heat assisted magnetic recording (HAMR) in hard disks.”
Another direction, the future of which Kuznetsov says is still being discussed, is on-chip photonic devices, “which potentially can be used to transmit light between different transistors on a chip, where light information transmission is faster than when using electric current. For that you need to confine light to very small scales. At the moment, what’s happening in silicon photonics is people use conventional waveguides to transmit on a chip or between chips. Yet with resonant antennas we can go down in scale further.”
However, the main application, and the one which Kuznetsov chose in his submission for the Harvey Prize, is that of flat optical devices and spatial light modulators. “The idea is to put an array of sub-wavelength antennas close to the chip and then apply voltage to each antenna, controlling the phase locally. Using that, I can create holograms. In fact, I can do whatever I want because I can fully control the phase of light.” What has been developed today, he says, is this kind of arrangement, only with fixed geometry, allowing for lenses with better resolution than standard optical microscopes, for example. “What this means is that you can create a nice hologram, but it would be fixed. However, what we need to do now to take that forward is to make the antennas switchable. If you can do that, you can create moving 3D holographic displays.”
Where this will really count is in augmented and virtual reality graphic displays. “In other words, things that we see in science fiction movies will become real. This is one of the reasons why nanophotonics is so important. Spatial light modulators exist now, but resolution of these devices is significantly above wavelength. This is because what is used in the process is a standard mirror with liquid crystal. Yet the resolution and viewing angle for that kind of hologram is very low as it is defined by distance between pixels. At the moment, this distance is in the order of a few microns. The limitation is not in technology, but physics, because there comes a point where mirrors don’t work as mirrors any more. You can only use mirrors down to about two or three microns, because after that it won’t reflect light, but will scatter it in all directions. Which is where nanophotonics comes in. Instead of using a mirror, you control the light using a nanoantenna, which allows you to see a hologram from a wider angle.”
The general public will first use nanoantennas in 3D holographic images on their smartphones or their TV screens. Yet beyond lifestyle applications, there are uses in medicine. If you do a Google search on nanophotonics, there’ll be plenty of results in the field of diagnosis. “Instead of seeing, for example, a two-dimensional scan of a heart, you will see the whole thing. This is a good way of showing how powerful this technology is in terms of how we receive information. It will create opportunities in education too”.
The market for three-dimensional images on flat electronic device screens will be overwhelmingly that of entertainment. However, when it comes to the idea of whether or not nanoantennas are stretching boundaries of smartphone technology simply because we can, Kuznetsov remains philosophical. “Yes of course, we will be seeing people on the train playing games and watching movies. This is simply the world that we live in. When you think about it, if we look back on the development of the touchscreen, these days we might think that this is nothing special. But, you have to remember that this transformed our lives. Everything changed. Look at what we can do on these devices now that we could never have predicted. The touchscreen changed the world and I think that the same will happen with holographic displays.”