Russian scientists have found a way to make lasers more precise and expand their capabilities. Researchers have more than doubled the working range of special crystals, without which some laser systems cannot operate. Now, such lasers can be tuned to emission regions that were previously almost inaccessible. This could be useful in medicine, industry, astronomy, and gas analysis.
The breakthrough in lasers was achieved by a team of scientists from South Ural State University (SUSU), Kuban State University (KubSU), and Lomonosov Moscow State University (MSU). Their model allowed for a significant expansion of the working range of silver thiogallate crystal for laser systems — from 10.6 to 21 µm.
This crystal is needed to produce mid-infrared radiation, but previously it was well-studied only up to a wavelength of 10.6 micrometers. Everything beyond that, in the “longer” part of the radiation, remained almost a “blind spot” for laser developers. To look into this inaccessible range, scientists used a method where one photon splits into two: they observed the “near” photon in a clear and studied region, and from it, reconstructed the properties of the “far” photon where precise measurements were previously too complex.
This method allowed the study of the properties of silver thiogallate crystal without complex and expensive equipment. The areas that could not be accurately measured before were reconstructed by scientists using special calculations – the Sellmeier equation. It helps to understand how light behaves inside a transparent material at different wavelengths.
The main practical result is that engineers will now be able to create lasers operating at wavelengths previously considered almost inaccessible. The model has been made publicly available, so other developers will be able to create new laser systems faster and fine-tune their characteristics more precisely. The work was carried out with financial support from the Russian government.
The development is considered particularly important for gas analytics. SUSU emphasized that many technical gases absorb light precisely in the 12–20 µm range. Now, lasers can be tuned more precisely to these spectral lines, which means industrial sensors can become more sensitive.