Using quantum optics to develop ‘uncrackable’ security
Even now, Pepijn Pinkse, Professor of Adaptive Quantum Technology at the University of Twente (UT), can look at his field of quantum optics with a childlike sense of wonder. ‘When I conduct experiments, I often catch myself thinking: wow, how is it possible that the natural world works like this?’
Pinkse and his research group study how light interacts with the environment, an area in which quantum properties play a vital role. He illustrates this using a laser pointer, shining the light so that a single, clear dot appears on a desktop in his office. Then Pinkse sticks a small piece of sellotape to the end of the laser pointer, and a complex pattern of tiny dots appears on the desk. ‘The nature of this pattern depends on the roughness of the tape; the thickness varies from one place to another and that’s what causes the complex scattering of light particles.’
The word ‘adaptive’ in his title refers to systems that allow Pinkse and his research group to fiddle with controls to influence and study the interaction between light particles. ‘The main example we use here in Twente is a spatial light modulator, or SLM for short. You can find this technology in a beamer, for example, which allows us to project images on a wall. This type of modulator contains thousands of pixels which act like the knobs on a control panel. By turning them up and down, we can play around and affect the light.’
A similar technology can be found in integrated photonic circuits, just one line of research in Pinkse’s group. ‘This approach has really taken off in recent years. Quix Quantum, a startup involving Jelmer Renema, is one example. Again, this technology centres on the interaction of light particles. Quix has succeeded in building a photonic quantum processor and is currently working on a photonic quantum computer, the first in Europe.’
Professor Pinkse is keen to emphasise that applications like these can only get off the ground thanks to the rock solid infrastructure on and around the UT campus for photonics: a technology that focuses on detecting, generating, transporting and processing light. ‘What makes Twente unique is that, for years now, we have had the capacity to make high-quality photonic hardware in our cleanrooms.’ He also praises the entrepreneurial spirit at UT. ‘At UT, no one is surprised if you want to start a company as a researcher. At some other universities, it’s a very different story.’
Pinkse himself deploys photonic hardware to create uncrackable security measures, also known as quantum-secure authentication. ‘Physical keys that cannot be copied with existing or foreseeable technology already exist but, here at Twente, we have found a way to make them even more secure using photons to produce a quantum state. Quantum computers hold promise for the future, but this is quantum technology that is operational here and now.’
Pinkse and his research group have developed a credit card secured by quantum technology. ‘The card contains a white piece of plastic, which we can read out using quantum light. The professor has even had talks with banks and investors about the credit card. ‘Unfortunately, they did not see the market potential. Having invested so many billions in the existing hardware, they seem prepared to take a few million in fraud losses as part of the deal. We have therefore shifted our focus to applications in fields where security is absolutely critical. For example, the kinds of cryptographic systems that secure government secrets.’
Applications like these make quantum optics a special field, Pinkse believes. ‘But at the same time these are also very fundamental questions. The beauty of quantum optics is that we can still conduct pioneering experiments right here at our own laboratories. You can’t say that about many fields of research. Often, the latest equipment is only available in a few places around the world. Whereas, I can just pop round the corner to my own lab. Not only that, but I can describe my workings using relatively simple mathematics. ‘When I conduct experiments, I still catch myself thinking: wow, how is it possible that the natural world works like this?’
Education
Professor Pinkse also does his best to instil this same fascination in his students. ‘It’s all about that childlike curiosity, which I feel myself. I want to get that sense of wonder across to my students, using real-life examples and stories. I try to encourage this curiosity in our own research group too: they should have the freedom to explore uncharted territory. Serendipity, finding something you weren’t necessarily looking for in the first place, is very important to me. I have seen plenty of examples of that in my career and it’s something I am keen to encourage.’
about Pepijn Pinkse
Pinkse studied physics at Leiden University and obtained his PhD at the University of Amsterdam. After a brief postdoc at the University of Konstanz, he spent ten years at the renowned Max-Planck Institute for Quantum Optics, working in Gerhard Rempe’s division. In 2009, he moved to the University of Twente, where his research has included pioneering work on quantum-secure authentication. For this work, he was awarded a Vici grant in 2013, the highest individual grant available from the Dutch Research Council (NWO). Since 2019, Pinkse has held the title of Professor of Adaptive Quantum Optics. He is also director of the Centre for Quantum Nanotechnology Twente (QUANT).
Press photos
These press photos can be used, please include the name of the photographer, Fokke Eenhoorn.