Russia has found a way to simplify and reduce the cost of laser production

Kaliningrad scientists have discovered the effect of luminescence – the glow of a substance without heating it – when exposed to infrared radiation on ytterbium oxide. Previously, this phenomenon was observed only with a combination of several rare-earth metals. The discovery will significantly reduce the cost and simplify the production of laser optics, as well as help achieve greater radiation power. This work was carried out as part of the project of the Russian Foundation for Basic Research with the support of the Government of the Kaliningrad Region (project No. 19-42-390002). Researchers Article published in Optics Communications Magazine.

When heated to certain temperatures, substances begin to emit light – electromagnetic energy in the visible region of the spectrum. Electrons, being at one of the highest energy levels, spontaneously go to lower, emitting part of the energy in the form of a quantum of light. However, there are types of luminescence excited by any other type of energy, except thermal. They are called luminescence. People use luminescent substances to create light sources, trying to minimize other forms of energy release – heating, chemical reactions, and so on.

In cooperative luminescence, the energy absorbed in two or more active centers of the luminescent molecule is transferred to one place from which it is emitted. In the process, long-wave (usually infrared) radiation is converted into a higher-energy short-wave (for example, visible light). This phenomenon is observed upon optical excitation of special “cooperative” phosphors — specially selected pairs of rare-earth ions — ytterbium, thulium, holmium, erbium, and others. In such a pair (Yb³⁺ and er³⁺; Yb³⁺ and but³⁺; Yb³⁺ and Tm³⁺or yb³⁺and Tb³⁺) one of the ions serves as a sensitizer, that is, it enhances susceptibility to light, and the other as an activator, that is, forms glow centers in the main substance. Rare earth metals are embedded in crystalline matrices, glass or ceramics and used in the manufacture of emitters, lasers, waveguides, energy converters and biosensors. The optical properties of these objects are largely due to their size, shape and surface structure, and the process of their creation is quite expensive and time-consuming.

Scientists from the I. Kant Baltic Federal University, together with colleagues from the Kaliningrad State Technical University, found that the same glow mechanism is realized when two ytterbium ions Yb interact³⁺. The researchers found that when exposed to infrared radiation on the powder of its oxide Yb₂O₃ a red glow occurs, that is, luminescence does not require the use of a second substance. They showed that the optical properties of this effect can be controlled by changing the power of the exciting radiation and its polarization — the plane in which the electromagnetic wave propagates.

Given the high cost of rare-earth metals, the use of ytterbium oxide alone in the manufacture of laser optics provides prospects for its significant simplification and cheapening. In addition, ytterbium resistance to extreme temperatures will allow the material to withstand powerful radiation. Also, the results obtained can be useful in creating energy converters in the near-infrared region and are used in optosensorics.

“The resulting effect can be used to improve night vision devices. Optics picks up infrared radiation – heat – and forms an image on its basis, and the ability of ytterbium oxide to amplify the signal will help to form a stronger stream, which will make the image much clearer than in devices whose lenses are made using traditional technologies, ”said one of the researchers , Senior Researcher, Scientific and Educational Center “Fundamental and Applied Photonics. Nanophotonics ”BFU Anna Tsibulnikova.

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