NPI SB RAS: Plasmon Interferometer

2024: Creation of a terahertz plasmon interferometer

Scientists from the Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences (INF SB RAS) have created a terahertz plasmon interferometer. The development will help you quickly select materials for plasmon wireless devices. Compared to ultra-high frequencies, the data transfer rate on terahertsev is an order of magnitude higher. This was announced on June 24, 2024 by representatives of the INF SB RAS.

strana-rosatom.ru

As reported, a plasmon interferometer is needed to study the optical svoy­stv of the surface of metals and films, on the basis of which plasmon integrated circuits are created. The device does not use electromagnetic waves, but surface plasmon polaritons - electromagnetic vibrations at the border between metal and dielectric material. The electromagnetic wave propagates along the surface of the material along with the wave of free charges. The characteristics of these charges carry information about the optical svoy­stvakh of the sample.

Plasmon integrated circuits are similar to radio electronics chips, only in them surface waves act as carriers of information, and the principle of operation of individual plasmon elements can fundamentally differ from classical analogues.

Modern signal transmission and processing devices, such as 4G, operate at ultra-high frequencies. The average wireless data transfer rate in the microwave range, depending on the class of devices, varies from 0.5 to 100 Gbps. To increase speed, the terahertz range is mastered. Telecommunications THz devices, including wireless communication systems such as the 6G, will have up to 1 Tbit/s. Due to the narrow directivity of the pattern of electromagnetic waves emitted and received by plasmon antennas, it will be possible to send information from the source to the receiver. This will increase its security. Such opportunities are of interest to high-tech corporations like Rosatom, which need to quickly transfer a large amount of data over secure channels. told Vasily Gerasimov, Senior Researcher, INF SB RAS Candidate of Physical and Mathematical Sciences

The field of application of THz-band devices is extensive: from security to space and medicine. Paper, most plastic materials and fabrics for terahertz waves are transparent, with their help you can detect metal objects, drugs, biological and chemical compounds. In world medicine, ophthalmic diseases and skin cancer are detected by terahertz waves. Terahertz telescopes record relict radiation - cosmic microwave background radiation that arose in the era of primary hydrogen recombination after the Big Bang and uniformly fills the Universe. These telescopes provide an opportunity to better study the early stage of the development of the universe.

The plasmon interferometer appeared as a result of complex research work of the NPI and the Moscow Scientific and Technological Center ­ Unique Instrumentation of the Russian Academy of Sciences. Two teams devoted more than 10 years to this work. The main technical help was the free electron laser in the NPI. Spectral brightness of radiation is 0.8-10 THz.

Its characteristics are monochromaticity, coherence, rearrangement of the wavelength of radiation over a wide range and, importantly, optimal average power. All this allowed us to go through many experimental difficulties and, step by step, develop a terahertz-band Michelson plasmon interferometer. told Vasily Gerasimov

One of the most important issues to be solved is what materials to use for plasmon schemes. At the disposal of scientists were samples of metals and conductors created by colleagues from other institutes, capable of working in the right range. The problem was that they were examined by classical spectroscopic methods and obtained data on the bulk svoy­stvakh of materials. The Novosibirsk scientists were important svoy­stva superficial.

The characteristics of plasmon ­ polaritons, and therefore the energy efficiency of plasmon circuits, and the quality of the information transmitted by them depend on the optical svoy­stv of the near-surface layer of the material and coatings with a thickness of tens of nanometers. Many domestic and foreign scientific groups were engaged in research in the field of THz plasmonics in the 1970s and 2000s, but stopped, as they faced great experimental difficulties. explained by Vasily Gerasimov

Experiments with terahertz waves lasted two years. They were attended by employees of two teams.

We learned how to generate plasmons, control their distribution and characteristics. We tested an interferometer on a free electron laser, selected the optimal operating modes. The findings are published in the journals Instruments and Experimental Techniques and Applied Sciences. Tests were carried out on metal films applied to the substrate by magnetron spraying at our institute. It turned out that the optical svoy­stva of the surface of the material strongly depend on the sputtering technology and the roughness of the substrate. This will be useful to colleagues who are engaged in X-ray mirrors for SKIF stations (Siberian Ring Photon Source. - "Lab. SR "). They also use metal films. told Vasily Gerasimov

Another area of ​ ​ application of the interferometer is the study of composite films from graphene nanoparticles. A team of researchers is testing the ability to apply integrated plasmon circuits to them for devices. 6G