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Russian scientists master using holograms to track microparticles

The biological applications this new technology holds are just as exciting

MOSCOW, April 21. /TASS/ Opticists from ITMO University have developed a rapid testing method that allows for evaluating the concentration and distribution of particles in transparent environments by using holograms, the ITMO’s press office reported.

The technique is applicable in engineering construction for ferreting out metal shavings in machinery oil, in studying plankton in water, and in tracking viruses in living cells. The study was published in the prominent journal Scientific Reports.

"Our rapid testing method provides real-time information on surroundings with an arbitrary percentage of particles and is ready to be implemented for industrial purposes," said Tatiana Vovk, research assistant at the Department of Photonics and Optoinfomatics at ITMO.

The scientists note that existing tools for analyzing particle contents, for example, microscopes, are time-consuming and some of them are not capable of dealing with environments containing a high concentration of particles. This motivated the researchers from ITMO to create a new analysis technique to track the distribution of microscopic particles in transparent surroundings. The basic idea rests on Gabor's holography - the easiest and first-ever type of holography.

In order to retrieve the distribution of particles in a sample, scientists first take a digital Gabor inline digital holographic image followed by extracting two 2D shots from the 3D-picture and then by comparing the snapshots with each other. Depending on the rate of similarity between the two shots, one can derive a correlation function which can be extrapolated for the whole surrounding volume. The whole computation takes only a few seconds.

The researchers have approved the technique and the experiments’ results have shown that this new approach is capable of rapid analysis of the concentration of particles in the surroundings, along with the distribution function of the particles and their transparency being defined as well.

Up till now, the researchers have shown only the method’s principle operating capabilities but they believe that the instantaneous registration of particles might be relevant for many areas. For instance, the automatic analyzers based on the suggested approach might track in the real-time mode the suspensions and aerosols flow, in particular, define the concentration of solid particles in the machinery oil. "When the components of a device get in contact, the oil lubricant can be polluted with metal shavings which wear down the whole mechanism. The analyzing device might be very helpful in evaluating the extent of the contamination and consequently the level of a device’s deterioration," Vovk added.

The biological applications this new technology holds are just as exciting. According to the researchers, the method will help study the purity of lake and river water by defining the rate of transparency of plankton. This feature is characteristic for the ecology of the whole basin as optical properties of microorganisms strongly depend on the state of the environment. Moreover, the technique might be used for counting viral particles in the living cells.