Effect of radiation on the optical properties of some ferroelectrics

This paper studies the effect of gamma-irradiation and impulsive irradiation with electrons on the optical properties of crystals used in nonlinear optics: potassium dihydrophosphate KH2PO4, and cesium dihydroarsenate CsH2AsO4. The authors used two types of crystals obtained by extraction of the condensate, lowering of the temperature and recirculation. The content of iron-group impurity atoms (A1, Cu, and Mg) were determined with the help of atomic absorption spectrometry and was less than 1.10-3 mole %. The samples were irradiated with a Co 60 gamma-ray source and impulsive irradiation with electrons was performed with a U-12 linear accelerator. A comparison of the spectra of gamma-irradiated single crystals and crystals irradiated with electrons shows that they are identical in the UV region. The impulse technique, however, enables observing the absorption bands which under gamma-irradiation are lost owing to the large increment of the optical density in the ultraviolet region and the shift of the absorption edge into the long-wavelength region