WARSAW: Scientists have created tiny \u201coptical tornadoes\u201d \u2014 swirling beams of light that twist like miniature whirlwinds \u2014 using a surprisingly simple setup based on liquid crystals. Instead of relying on complex nanotechnology, the team used self-organizing structures called torons to trap and manipulate light, causing it to spiral and rotate in intricate ways.<\/p>\n
Even more impressively, they achieved this effect in light\u2019s most stable, lowest-energy state, making it far easier to generate laser-like beams with these unusual properties.<\/p>\n
Can light spin like a whirlwind? Researchers have now shown that it can. Scientists from the Faculty of Physics at the University of Warsaw, the Military University of Technology, and the Institut Pascal CNRS at Universite Clermont Auvergne have created swirling \u201coptical tornadoes\u201d inside an extremely small structure.<\/p>\n
The advance points to a new way of building miniature light sources with complex shapes, which could support simpler and more scalable photonic devices for optical communication and quantum technologies.<\/p>\n
\u201cOur solution combines several fields of physics, from quantum mechanics, through materials engineering, to optics and solid-state physics,\u201d explains Prof. Jacek Szczytko from the Faculty of Physics at the University of Warsaw, the leader of the research group.<\/p>\n
\u201cThe 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,\u201d added Szczytko.<\/p>\n
What Is an Optical Vortex?<\/p>\n
\u201cYou can think of it as an optical vortex,\u201d says Dr. Marcin Muszynski 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.<\/p>\n
\u201cThe light wave twists around its axis, and its phase changes in a spiral manner. Moreover, even the polarization \u2014 the direction of oscillation of the electric field \u2014 begins to rotate,\u201d added Marcin.<\/p>\n
These structured light states are attractive for applications such as quantum communication and controlling microscopic objects. However, producing them has typically required complicated nanostructures or large experimental systems.<\/p>\n
Liquid Crystals Offer a Simpler Path<\/p>\n
The team chose a different strategy. \u201cInstead 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,\u201d explains Joanna Medrzycka, 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.<\/p>\n
Within this material, special defects known as torons can form. \u201cThey 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,\u201d Medrzycka explains. \u201cThese 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.\u201d<\/p>\n
A \u201cSynthetic Magnetic Field\u201d for Light<\/p>\n
\u201cSpatially variable birefringence, that is, the difference in the propagation of different polarizations of light, acts like a synthetic magnetic field,\u201d explains Dr. Piotr Kapuscinski of the Faculty of Physics at the University of Warsaw. \u201cWe call it \u2018synthetic\u2019 because its mathematical description resembles the behavior of a magnetic field, even though physically it isn\u2019t there. As a result, light begins to \u2018bend,\u2019 much like electrons moving in cyclotron orbits.\u201d<\/p>\n
To strengthen the effect, the toron was placed inside an optical microcavity, a structure made of mirrors that repeatedly reflects light and keeps it confined for longer periods. \u201cThis makes the field much stronger,\u201d says Dr. Muszynski. \u201cAdditionally, we can control the size of the trap, and thus the properties of the light, using an external electric voltage.\u201d<\/p>\n
Stable Light Vortices in the Ground State<\/p>\n
The most striking result came next.<\/p>\n
\u201cIn typical systems, light carrying orbital angular momentum appears in excited states,\u201d explains Prof. Guillaume Malpuech from Universite Clermont Auvergne and CNRS, who, together with Prof. Dmitry Solnyshkov and post-doc Daniil Bobylev, developed the theoretical model of the phenomenon. \u201cFor 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.\u201d<\/p>\n
\u201cThis makes it much easier to achieve lasing,\u201d emphasizes Prof. Szczytko. \u201cLight naturally \u2018chooses\u2019 this state because it is associated with the lowest losses.\u201d<\/p>\n
To confirm this, the researchers introduced a laser dye into the system. \u201cWe obtained light that not only rotates but also behaves like laser light: it is coherent and has a well-defined energy and emission direction,\u201d says Dr. Marcin Muszynski.<\/p>\n
Toward Simpler Photonic and Quantum Technologies<\/p>\n
\u201cIt\u2019s interesting that our approach draws inspiration from very advanced theories involving a so-called vectorial charge,\u201d adds Prof. Dmitry Solnyshkov \u201cSo, in a way, we\u2019ve managed to make photons behave not even like electrons, but like quarks, the charged particles which make up protons.<\/p>\n
\u201cThis discovery opens a new pathway for creating miniature light sources with complex structures. \u201cIt shows that instead of relying on complex nanotechnology, we can use self-organizing materials,\u201d concludes Prof. Wiktor Piecek from the Military University of Technology. \u201cIn the future, this may enable simpler and more scalable photonic devices, for example for optical communication or quantum technologies.\u201d (ANI)<\/p>\n","protected":false},"excerpt":{"rendered":"WARSAW: Scientists have created tiny \u201coptical tornadoes\u201d \u2014 swirling beams of light that twist like miniature whirlwinds \u2014…\n","protected":false},"author":2,"featured_media":646392,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[49,48,66],"class_list":["post-646391","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ca","tag-canada","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/646391","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=646391"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/646391\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/646392"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=646391"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=646391"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=646391"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}