Breakthrough in Photonics: NNSU invents a way to amplify terahertz radiation

Scientists from the Department of General Physics of the Faculty of Radiophysics at Nizhny Novgorod State University (NNSU) have developed a new method for generating multi-cycle terahertz waves, which significantly increases the radiation power and flexibly controls its parameters. This was reported by the university's press service.

The head of the research, Head of the Department of General Physics Mikhail Bakunov, noted that the generation of multi-period electromagnetic pulses in the terahertz range is one of the most challenging tasks in modern photonics. Conventional methods of laser technology and electronics do not work in this spectral range.

The non-linear optical approach developed at NNSU allows the formation of dozens of oscillations of the terahertz field using a single short laser pulse and scaling the radiation power by increasing the energy of the laser pumping.

Usually, expensive multilayer crystals with alternating non-linear properties are used to obtain terahertz radiation, where each layer generates one wave cycle. This method limits the power and requires the creation of new structures to change the frequency.

NNSU scientists proposed replacing this scheme with a lithium niobate single crystal with a specially selected orientation of the axes. This made it possible to tune the radiation frequency by simply changing the angle of incidence of the laser beam and increase the power by using large crystals and wide laser beams of high intensity.

The results of theoretical calculations were confirmed experimentally. The new method proved to be more efficient and economical than existing solutions. Colleagues from the University of Pécs (Hungary) are already considering the technology as a promising tool for particle acceleration. Currently, Russian researchers are selecting new materials that can replace lithium niobate and make the technology even more productive.

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