Researchers generated stable vortex light in its lowest-energy state using liquid crystal traps and optical confinement.
Can light spin like a miniature tornado? Researchers have now shown that it can. Teams from the University of Warsaw, the Military University of Technology, and Institut Pascal CNRS at Université Clermont Auvergne have created so-called optical tornadoes inside a very compact setup. The advance could lead to smaller light sources with complex internal patterns, potentially simplifying technologies used in optical communication and quantum systems.
“Our solution combines several fields of physics, from quantum mechanics, through materials engineering, to optics and solid-state physics,” explains Prof. Jacek Szczytko from the Faculty of Physics at the University of Warsaw, the leader of the research group. “The inspiration came from systems known from atomic physics, where electrons can occupy different energy states. In photonics, a similar role is played by optical traps, which confine light instead of electrons.”
“You can think of it as an optical vortex,” says Dr. Marcin Muszyński from the Faculty of Physics at the University of Warsaw and Department of Physics City College of New York, the first author of the study. “The light wave twists around its axis, and its phase changes in a spiral manner. Moreover, even the polarization – the direction of oscillation of the electric field – begins to rotate.”
These types of structured light fields have drawn attention for their ability to encode information and manipulate extremely small objects. However, producing them has typically required either intricate nanoscale fabrication or large and complex laboratory setups, which limit how easily they can be used in practical devices.
Simplifying vortex light generation
To overcome those limitations, the researchers chose a different strategy based on soft, self-organizing materials. “Instead of building complex systems, we used a liquid crystal, a material with properties intermediate between a liquid and a solid. Although it can flow like a liquid, its molecules arrange themselves in an ordered way, maintaining a fixed orientation and relative positions, much like in a crystal,” explains Joanna Mędrzycka, a nanotechnology student at the Faculty of Physics, University of Warsaw, who, together with Dr. Eva Oton from the Military University of Technology, prepared the liquid crystal samples.
Within this material, the team created defects known as torons, which act as tightly wound regions where molecules twist in a defined pattern. “They can be imagined as tightly twisted spirals, similar to DNA, along which the liquid crystal molecules are arranged. If such a spiral is closed by joining its ends into a ring resembling a doughnut, we obtain a toron,” Mędrzycka explains. “These structures act as microscopic traps for light. A key step was creating an equivalent of a magnetic field for photons. Although light does not respond to magnetic field like electrons do, a similar behavior can be achieved for light by other means.”
– Spatially variable birefringence, that is, the difference in the propagation of different polarizations of light, acts like a synthetic magnetic field,” explains Dr. Piotr Kapuściński of the Faculty of Physics at the University of Warsaw. “We call it ‘synthetic’ because its mathematical description resembles the behavior of a magnetic field, even though physically it isn’t there. As a result, light begins to ‘bend,’ much like electrons moving in cyclotron orbits.”
Confinement enables strong light control
To strengthen this effect, the toron structure was placed inside an optical microcavity, a mirrored environment that keeps light bouncing back and forth for extended periods. This confinement increases how strongly the light interacts with the structure around it. “This makes the field much stronger,” says Dr. Muszyński. “Additionally, we can control the size of the trap, and thus the properties of the light, using an external electric voltage.”
The outcome of this setup led to a particularly important result.
“In typical systems, light carrying orbital angular momentum appears in excited states,” explains Prof. Guillaume Malpuech from Université Clermont Auvergne and CNRS, who, together with Prof. Dmitry Solnyshkov and post-doc Daniil Bobylev, developed the theoretical model of the phenomenon. “For the first time, we managed to obtain this effect in the ground state, i.e., the lowest-energy state. This is significant because the ground state is the most stable and the easiest for energy to accumulate in.”
“This makes it much easier to achieve lasing,” emphasizes Prof. Szczytko. “Light naturally ‘chooses’ this state because it is associated with the lowest losses.”
Ground state unlocks stable vortex lasing
To confirm the behavior, the researchers introduced a laser dye into the system, allowing the light to amplify. “We obtained light that not only rotates but also behaves like laser light: it is coherent and has a well-defined energy and emission direction,” says Dr. Marcin Muszyński.
“It’s interesting that our approach draws inspiration from very advanced theories involving a so-called vectorial charge,” adds Prof. Dmitry Solnyshkov. “So, in a way, we’ve managed to make photons behave not even like electrons, but like quarks, the charged particles which make up protons.
“This discovery opens a new pathway for creating miniature light sources with complex structures. “It shows that instead of relying on complex nanotechnology, we can use self-organizing materials,” concludes Prof. Wiktor Piecek from the Military University of Technology. “In the future, this may enable simpler and more scalable photonic devices, for example, for optical communication or quantum technologies.”
Reference: “Ground-state orbital angular momentum lasing from liquid crystal torons embedded in a microcavity” by Marcin Muszyński, Daniil Bobylev, Piotr Kapuściński, Przemysław Oliwa, Joanna Mędrzycka, Eva Oton, Rafał Mazur, Przemysław Morawiak, Wiktor Piecek, Przemysław Kula, Dmitry Solnyshkov, Guillaume Malpuech and Jacek Szczytko, 13 March 2026, Science Advances.
DOI: 10.1126/sciadv.aeb6167
Funding: National Science Centre (Poland), Ministry of National Defense Republic of Poland Program, European Union’s Horizon 2020 program, ANR.
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