It all started with Nicolas Roy's trip to Stanford. Nicolas is a PhD student in the Department of Physics and a member of the NISM and NaXys Institutes. The purpose of the visit to Stanford was to develop expertise at UNamur on a new method of simulating twisted photonic crystals, recently published by the prestigious university. Following discussions during the stay at Stanford, avenues for collaboration emerged, notably that of continuing research related to one of their publications in order to try to make a device that allows the direction of the light beam to be manipulated as efficiently and compactly as possible.  The gamble paid off, as the theoretical study predicts a device measuring 6 microns (the size of a hair)!  What's more, it is very energy efficient.  In practical terms, it could be used to track satellites, for example, without moving the transmitter or receiver, which is complicated in a photonic circuit.  Another practical application is being studied for Meta, a company that wants to reduce the size of virtual reality headsets to a simple pair of glasses... 

During his PhD, and based on a Stanford team publication entitled "Theory for Twisted Bilayer Photonic Crystal Slabs", Nicolas reproduced the simulation method and developed an analytical model of the numerical simulations. The use of these inexpensive simulations has made it possible to find the photonic structures most capable of deflecting light in a controlled manner. The analytical model, in turn, provides an explanation for what has been observed, and thus a better understanding of what's going on. In short, it opens up prospects for simpler fabrication of future devices.

The research teams collaborating on this study are working on twisted photonic crystals, i.e. two-dimensional materials formed, for example, from two superimposed and structured layers of silicon, and their interaction with light. 

In designing an analytical model, Nicolas Roy also used a theory that has been known since the 1960s: lattice networks. A lattice network is a plane diffraction network with a sawtooth profile.  In concrete terms, it resembles the roofs of old factories.  The novelty he brought to this concept is that it allows us to understand the mechanism that controls the angle of the light beam's exit thanks to the twist between the two layers. In doing so, he identified that the system acted similarly to a lattice grating. The team, using meta-models, was able to concentrate the light in a very specific direction with 90% efficiency.

What is the purpose of this type of twisted structure? To control light and ultimately create systems that can slow it down or even stop it.

This twist technique therefore opens up many unexplored possibilities in photonics by adding a degree of control over light. The researchers are continuing their work in this area, continuing their fruitful collaboration with Professor Fan's team, Stanford University.  

It looks like there's no end in sight to the twisting at the University of Namur! 

The Belgian team

• Professor Michael Lobet (UNamur, Harvard University)
• Professor Alexandre Mayer (UNamur)
• Dr Nicolas Roy (UNamur)

The American team

• Professor Shanhui Fan (Stanford University)
• Dr Beicheng Lou

The researchers thank UNamur, and more specifically the Department of Physics and the NISM Institute for funding Nicolas Roy's trip, the Institut naXys for its support in this project, the PTCI technology platform, whose supercomputers made this study possible, as well as the FNRS for funding the research mandates of Michaël Lobet and Alexandre Mayer.

• Michaël Lobet, the physicist of the invisible who makes light twist
• Following in Einstein's footsteps: old theories, new perspectives
• Publication on light observation in Nature Communications

In the picture, from left to right: (top) Pierre Louette, Director of the Physics Department; François Briard, Head of the Science Portal Group (CERN); Julien Colaux, IBA specialist, physics researcher; Boris Hespeels, biology researcher; Alexandre Mayer, physics researcher; Anne-Catherine Heuskin, physics and biophysics researcher. (bottom) André Füzfa, astrophysicist and mathematics researcher; Serge Mathot, Applied Physicist (CERN) and Michaël Lobet, physics researcher.

The love affair between CERN and UNamur goes back a long way. CERN's accelerator complex and experimental program are very different and much larger than those of UNamur's Physics Department, but the fields in which the two institutions work have much in common.

In addition, both guests have a personal history with UNamur. The Physics Department was pleased to welcome Serge Mathot, Referent Applied Physicist (CERN) and alumni of the UNamur Physics Department (1992), as well as François Briard, Group Leader Science Portal (CERN), and alumni of the UNamur Faculty of Computer Science (1994).

The activities began with a meeting between the guests, Rector Annick Castiaux, Vice-Rector for Research Carine Michiels, Physics Department Director Pierre Louette and several other members of the Physics and Biology Department. After a general presentation of the University, the participants pointed out the missions shared by both institutions: research and the transfer of technology and knowledge, service to society, scientific popularization and education and training.

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Physics lunch - CERN presentation

The physics lunch is the monthly meeting between students and members of the physics department and a professional, alumni or not, coming to explain his or her background and what he or she does on a daily basis as a physicist.

During this meeting, attended by around 80 people, François Briard and Serge Mathot presented CERN, the world's largest laboratory for particle physics. CERN's mission is to understand the most elementary particles and the laws of our universe.

At the end of the seminar, the students came away with stars in their eyes. Indeed, opportunities for internships or even first jobs at CERN are possible for physicists but also in many other fields.

Some internship programs at CERN are particularly well suited to the needs of young Belgian students.

The vast majority of physicists working with CERN (over 13,000) are in fact sent to CERN for varying periods of time by their employing national research institutes. CERN offers an exceptional opportunity to develop international experience under excellent conditions, in an environment that is unique in the world! What an inspiration for our young students!

The projet d'Action Recherche Concertée (ARC) PHOENIX aims to renew our understanding of medieval parchments and ancient coins. Artificial intelligence will be exploited to analyze the data generated by material characterization.

This joint study between the Department of Physics and the Namur Institute of Structured Matter (NISM) and the Department of History and the Institut Patrimoines, Transmissions, Héritages (PaTHs) will address questions relating to the production chain and use of these objects and materials in past societies.

At the same time, Serge Mathot presented a seminar in heritage science attended by some 50 people. In particular, he presented his research and the brand-new ELISA accelerator: a miniaturized gas pedal capable of delivering a 2 MeV proton beam used to perform real measurements at the Science Portal.

Having the opportunity to exchange views with François Briard, Group Leader of the CERN Science Portal is a rare opportunity. Comparing outreach activities has opened up new avenues, discovering and sharing approaches, assessing what works and what doesn't, depending on the target audience. A highly satisfying enrichment for the members present from Confluent des Savoirs (CDS), the University of Namur's research outreach and dissemination service.

Professor Anne-Catherine Heuskin and Dr. Boris Hespeels are currently working on the BEBLOB project, a Belspo project with ESA support, as part of the UNIVERSEH (European Space University for Earth and Humanity) alliance. They are particularly interested in its astonishing ability to withstand high doses of radiation.

Anne-Catherine Heuskin also works in radiobiology. Particles are used to irradiate cancerous cells in order to destroy their genetic material and prevent them from proliferating: this is the basis of radiotherapy and proton therapy.

The meeting confirmed the willingness of FaSEF and UNamur to get involved in coordinating the Belgian National Teacher Programme in French-speaking Belgium, which CERN intends to relaunch in 2026. Consideration was also given to other avenues for teacher training, such as CERN's forthcoming involvement in the "Salle des Pros", the training venue for the various players involved in teacher training at UNamur.

The TRAKK is Namur's creative hub supported by 3 complementary partners in the field: BEP, KIKK, and UNamur. In addition to the venue, François Briard was able to visit the ProtoLab , which bridges the gap between ideas and industry by being a decentralized research and development hub accessible to SMEs and project leaders by offering advanced support in prototyping products or services.

Graduating in law and information technology management (DGTIC) in 1994 after his bachelor's and master's degrees in computer science in 1993, François Briard works at CERN, the European Organization for Nuclear Research in Geneva, the world's largest particle physics laboratory.

During his school career, which was 100% at UNamur, he was vice-president of the Régionale namuroise and student delegate during his years as a candidate in economic and social sciences, computer science option.

Thanks to the multidisciplinary training provided at UNamur, he was able to seize several opportunities to redirect his career at CERN, where he was an information systems engineer from 1994 and then, from 2014, redirected his career until he became Group Leader of the Science Portal, which is CERN's general public communications center.

Serge Mathot obtained his doctorate in applied sciences from UNamur in 1992, following his bachelor's degree in physical sciences in 1985.

He then carried out a post-doctorate at the Joint Research Center (EU science hub) in Geel, which aims to bring together multidisciplinary skills to develop new measurement methods and tools such as reference materials.

He perfected his expertise in physical metallurgy before joining CERN in 1995 as a Referent Applied Physicist. He has worked on numerous research projects (CLOUD, MACHINA, ELISA...) and developed numerous parts for the manufacture of CERN's gas pedals.

CERN, the European Organization for Nuclear Research, is one of the world's largest and most prestigious scientific laboratories. Its vocation is fundamental physics, the discovery of the constituents and laws of the Universe. It uses highly complex scientific instruments to probe the ultimate constituents of matter: the fundamental particles. By studying what happens when these particles collide, physicists understand the laws of Nature.

The instruments used at CERN are particle gas pedals and detectors. Gas pedals carry beams of particles at high energies to collide with other beams or fixed targets. Detectors observe and record the results of these collisions.

Founded in 1954, CERN is located on either side of the French-Swiss border, near Geneva. It was one of the first organizations on a European scale and today has 25 member states, including Belgium.

The three scientific experiments were selected from 29 projects for "their scientific value, technical feasibility and budgetary compatibility", states the public service of Federal Science Policy (Belspo).

Historically, Belgium has built up notable expertise and influence within the European Space Agency (ESA). Today, UNamur finds itself at the heart of an experiment that will be deployed during Belgian astronaut Raphaël Liegéois's stay aboard the ISS in 2026. The BeBlob project, conducted at the interface of biology and physics, aims to study Physarum polycephalum, commonly known as a "blob".

Boris Hespeels is a researcher at the ILEE Institute and the Beblob project leader alongside Anne-Catherine Heuskin, a researcher at the Narilis Institute. "We're also interested in its amazing ability to dry out completely and survive extreme stresses, including the vacuum of space, extreme temperatures or even high doses of radiation causing massive DNA damage," the two Namur researchers continue.

Building on their experience gained on previous ISS missions with other biological models, UNamur teams have developed a new miniaturized "vessel" for carrying different blob samples. In orbit, the astronaut will rehydrate the samples, which will then have to adapt to their new environment. The objectives are twofold: firstly, to assess the effects of the orbital environment on blob metabolism; secondly, to study DNA repair in samples previously irradiated on Earth by massive doses. Scientists will analyze how this organism repairs its genome in microgravity, and determine whether this process is altered by spaceflight.

This work should make it possible to identify key players in cell protection and repair under extreme conditions. Combined with the many experiments carried out at UNamur, they could ultimately lead to the development of new molecules capable of protecting astronauts, preserving fragile biological samples or even limiting the side effects of radiotherapy by protecting patients' healthy cells.

Discover the other scientific experiments selected to be carried out on board the International Space Station (ISS) during astronaut Raphaël Liégeois's mission in 2026

UNIVERSEH (European Space University for Earth and Humanity) is part of the "European Universities" initiative promoted by the European Commission. Its ambition is to develop a space to meet the societal, social and environmental challenges arising from European space policy.

• This research, still at the experimental stage, is based on a new formulation of electrochromic material: MoWOx, a mixed molybdenum-tungsten oxide
• This advance makes it possible to envisage "dual-band" functionality, i.e. selective and independent modulation of incoming light and heat flows
• The results have been published in the journals Advanced Optical Materials and ACS Applied Optical Materials

Scientists from the University of Liège (ULiège) and the University of Namur (UNamur) have developed an innovative electrochromic material capable of independently regulating light and heat in buildings. This breakthrough, based on a mixed molybdenum-tungsten oxide (MoWOx), paves the way for even more efficient and energy-saving smart windows.

Electrochromic windows are smart glazings capable of modulating their coloration, or more generally their state of transparency or opacity, when an external electric current is applied to it. This property makes it possible to control the intensity of solar radiation entering a building, without the need for blinds or curtains. This type of window is already manufactured industrially and used technologically in some buildings, but current products do not allow separate control of visible light (VIS) and near-infrared radiation (NIR), respectively linked to incident brightness and heat.

Researchers at ULiège and UNamur, thanks to support from the Fonds de la Recherche Scientifique (FNRS), have thus developed a new formulation of electrochromic material, entitled MoWOx, based on a "dual-band" functionality enabling selective and independent modulation of incoming light and heat fluxes.

Through this new formulation, the scientific teams have demonstrated the occurrence of an innovative optical mode, known as "warm", for the first time for this type of oxide. In this mode, the glass remains transparent to infrared radiation, allowing heat to pass through, while only partially filtering out visible light. This feature is particularly interesting for cold climates and winter periods, where maximizing solar heat gain while reducing solar glare can significantly reduce building energy consumption, particularly in terms of heating and artificial lighting.

This "dual-band" functionality is based on the incorporation of nanostructured plasmonic compounds into the smart glass. A plasmonic material is one whose free electrons can oscillate collectively under the effect of light. It can then selectively absorb, reflect or scatter light, depending on its composition and structure. And it is precisely in the application of these plasmonic properties of MoWOx to the case of smart glazing that this innovation lies.

On this basis, the composition and morphology of plasmonic nanostructures directly influence the optical selectivity of filtering, enabling glazing to be tailored more precisely to users' needs.

Future intelligent glazing incorporating these new components could ultimately revolutionize energy management in buildings. In a context where the energy transition remains a top priority, these innovative windows will help to achieve carbon neutrality targets and build near-zero energy buildings.

Florian Gillissen, researcher at the University of Liège and first author of the paper published in Advanced Optical Materials:"Thanks to this technology, we can adjust the transmission of light and heat through windows in real time, which represents a giant step forward for the energy optimization of buildings."

Professor Michaël Lobet, FNRS Qualified Researcher and first author of the paper published in ACS Applied Optical Materials: "Theoretical and numerical modeling was carried out at UNamur in Professor Luc Henrard's team, while material synthesis and characterization was carried out under the direction of Professor Rudi Cloots and Dr. Anthony Maho from the University of Liège. It is these synergies between theoretical modeling and fabrication that have enabled the characterization of these MoWOx materials."