In a recent study published in Nature Communications, physicists from Singapore and the UK have revealed an optical analog of the Kármán vortex street (KVS). This optical KVS pulse showcases intriguing parallels between fluid transport and the energy flow of structured light. Lead author Yijie Shen from Nanyang Technological University describes the light pulse as having a field structure similar to a von Kármán vortex street, a pattern of swirling vortices seen in fluid and gas dynamics.
The structured light presented in the study exhibits a robust topological structure of skyrmions in condenser matter. Unlike previous work on optical skyrmionic beams and pulses, the skyrmionic field configuration in nondiffracting supertoroidal pulses (NDSTPs) persists upon propagation over arbitrary distances without being limited by diffraction.
The researchers anticipate that NDSTPs could inspire various applications such as light-matter interactions, super resolution microscopy, and metrology. Skyrmions, which are sophisticated topological particles resembling nanoscale magnetic vortices, were originally proposed by Tony Skyrme in 1962 as a unified model of the nucleon.
Unlike known optical skyrmions that do not propagate or rapidly collapse upon propagation, the light pulses proposed in the study do not spread during propagation. This enables the skyrmionic field structures to persist as the KVS pulse propagates, allowing for the study of the propagation dynamics of electromagnetic skyrmionic fields.
Potential Applications
The researchers believe that the deeply subwavelength singularities of these pulses could have applications in metrology and spectroscopy of toroidal excitations in matter. Furthermore, the unique properties of these pulses could be leveraged for long-distance information transfer encoded in their topological features, with potential applications in telecommunications, remote sensing, and LiDAR.
The Kármán vortex street, a classical flow pattern of swirling vortices, is highly organized and known for its aesthetic beauty and immense power. The pattern typically consists of two sequences of vortices, each with circulations of opposite signs. The intersection of science and the humanities is highlighted by the painting at the Church of St Dominic in Bologne, Italy, depicting interlaced vortices behind St. Christopher.
The historical significance of the KVS is exemplified by the Tacoma Narrows Bridge incident in 1940. The suspension bridge, completed in just four months, suffered damage due to the generation of vortex streets caused by its improper design. This event served as humanity’s first recognition of the immense power of the Kármán vortex street.
Overall, this study sheds light on the fascinating intersection of science and light, demonstrating the potential for innovative applications and insights into the propagation dynamics of structured light pulses.
Leave a Reply