Characteristics of electromagnetic radiation from quartz, lithium niobate, and polymethyl methacrylate samples subjected to impact loading

The formation of a crack in quartz and lithium niobate single crystal samples, as well as in a polymethyl methacrylate sample, which is accompanied by the generation of electromagnetic radiation at its propagation through the bulk of the samples, has been studied. It has been shown that the onset time of the mechanical failure of samples correlates with the intense emission of ultrahigh-frequency broadband radiation from them. The frequency characteristics of radiation have been measured by a broadband antenna and a broadband oscilloscope. It has been shown that optical flashes correlate with ultrahigh-frequency radiation pulses. The phenomenon is attributed to induced triboluminescence. Radiation is generated due to the appearance of cracks in the samples with the formation of charges on their surface and subsequent field electron emission due to the generation of a high electric field gradient.