MOSCOW, July 24– . NRU MIET scientists proposed a new technology for creating elements for information display devices as part of a research team of developers. According to them, the use of laser pulses will speed up and reduce the cost of producing metasurfaces for next-generation displays and various optical systems. The results of the study are published in Applied Surface Science.
Metasurfaces are called structures with a periodic pattern (structure) that can control electromagnetic waves, in particular light. As a basis, dielectric, metallic, and also phase-changing materials can be used. The latter are able to change the phase state, and, as a result, properties depending on external radiation, said at the National Research University MIET (NRU MIET).
Based on metasurfaces made of phase-changing material GST (compounds of the germanium-antimony-tellurium system), scientists are developing new compact devices that can display information using light waves. These include ultra-thin displays, some augmented and virtual reality headsets, as well as holographic projectors, the NRU MIET specified. url=»https://ria.ru/20230414/ochki-1865212443.html» data->
However, the process of nanostructuring the film surface to transform it into a multifunctional surface is still carried out using the labor-intensive and costly lithography technology. So, the necessary image of the metasurface must first be created on a template (mask), and then transferred to the object in the selected resolution, the university noted.
To reduce the cost of film structuring, as well as process NRU MIET, IGIC RAS, MIPT, FIAN RAS and RSPU im. AI Herzen use laser pulses instead of lithography.
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“Using ultrashort pulse laser irradiation, it is possible to create ordered nanostructures on GST faster and easier. To form an ordered surface, we use pre-ablation processes, that is, which precede the destruction of the material under the action of a laser. The main advantage of the solution is that the pulses trigger the self-organization of structures on the surface, which means that they do not need to be «drawn», — explained Sergei Kozyukhin, professor at the Institute of Advanced Materials and Technologies of the NRU MIET.
The scientist added that depending on the intensity and/or number of pulses, three different types of structures can form, and the most curious of them is periodically arranged nanospheres of the same size. These are quite difficult shapes to form, the radius of which can be up to 150 nm.
Moreover, earlier in these materials they could not be obtained without the use of additional technologies. Now, apart from the laser facility and the films themselves, no equipment is required to obtain uniform nanospheres, Kozyukhin noted.
“The calculations and experiments we have carried out suggest that the spheres are formed as a result of the decay of molten thin filaments. At the same time, an increase in the energy of laser exposure causes mass transfer processes, which leads to the transformation of chains of nanospheres into a periodic relief,” said Tatiana Kunkel, one of the authors of the study.< br />This technology makes it possible to create highly ordered nanolenses and optical nanogratings, which are supposed to be further integrated into various optical systems, including information display systems.
Research is carried out within the framework of the Russian Science Foundation grant No. objects formed in the laboratory «Materials and Devices for Active Photonics» of NRU MIET with the support of the federal program of strategic academic leadership «Priority-2030».