Temperature dependences of the optical characteristics of ZnMgSe single crystals

The temperature dependences of the refractive index of wide-gap Zn_{1 − x} Mg _x Se (x ∼ 0.5) single crystals are measured. It is established that, in the temperature range 300–530 K, the value of dn/dT for such crystals grown by the vertical Bridgman method is 9.31 × 10⁻⁵ at λ = 0.63 μm and 5.29 × 10⁻⁵ at λ = 10.6 μm. The obtained values of the coefficients dn/dT for hexagonal Zn_{1 − x} Mg _x Se single crystals are close to the corresponding values for cubic ZnSe single crystals and are much lower than those for hexagonal CdS. Examples of practical application of single crystals of the ZnMgSe substitutional solid solution as a thermostable material for polarization optical elements in the IR range are given.