Scientists at Samara University, together with colleagues from the Russian Academy of Sciences, have developed a new method for creating optical elements that can be used to improve devices for transmitting data by a laser beam in the atmosphere and biomedical devices. The research results are published in Optics Express.
Russian scientists have developed a new approach to constructing metasurfaces, on the basis of which it is possible to create optical elements for devices that allow to control the polarization and phase of electromagnetic waves, as well as create light fields with previously unexplored properties, including unique laser beams.
“We have developed an optical element based on a metasurface and demonstrated its efficient operation: the simultaneous formation and focusing of a special laser beam with a vortex polarization structure. In the focus of such a beam, the light energy partially spreads towards the source, which is impossible when focusing classical laser beams,”commented the author of the study, associate professor of the Department of Technical Cybernetics at Samara University Dmitry Savelyev.
The scientist also noted that higher order metasurfaces provide a large total backflow of energy. That is, laser beams formed by polarizing elements are resistant to interference arising from the transmission of information in various turbulent media, for example, in the Earth's atmosphere.
The scientist explained that the realized metasurfaces allow creating new types of optical traps. They work like a vacuum cleaner: the backward flow of energy near the optical axis forces the particles to move towards the source.
In addition, according to experts, by combining a polarizer with a focusing element in one element, it is possible to create a large backflow of energy near the optical axis. This will help improve optical tweezers, laser cutting and engraving in biology, medicine and material handling, and reduce the number of optical elements in devices.
“Polarization control allows the creation of light fields with new properties. By changing the structure of the laser beam, you can change the nature of the impact on the object, and this is very important for laser cutting and engraving in the processing of materials,”said Dmitry Saveliev.