Birefringence of Mechanically Stressed Potassium Tetrachlorine Zincanate Crystals

The spectral and baric dependences of the birefringence $Δn_{i}$ of $K_{2}ZnCl_{4}$ crystals were studied. It is shown that the dispersion $Δn_{i}(λ)$ is normal and sharply increases on approaching the absorption edge. It is established that the uniaxial pressures do not change the character but only the values of the dispersions $dΔn_{i}$/dλ and temperature dependences of $dΔn_{i}$/dT