Photoelastic properties of potassium sulfate crystals

The spectral dependences of the absolute piezo-optic coefficients of potassium sulfate crystals are studied and their insignificant dispersion dependence is established. The matrix of elasto-optic coefficients $p_{in}$ of these crystals is filled using the values of elastic stiffness coefficients and absolute piezo-optic coefficients. The coefficient of the acousto-optic efficiency $M_2$ is estimated and it is shown that, considering the highest values, it is more than an order of magnitude higher than that of quartz and strontium borate crystals. Taking into account the short-wavelength boundary of the transparency region of potassium sulfate crystals ($\sim$170 nm), it is proposed to use them for acousto-optic modulation of ultraviolet radiation.