Thermal shocks influence on the growth process and optical quality of Nd: YAG crystal

In this paper, the effect of two kinds of thermal shocks on the quality of Nd:YAG single crystal grown by Czochralski method have been investigated. The shocks induced by unexpected change in water flow of cooling system, have a drastic influence on the stability of growth process. This is the intensity and duration of the shocks that affect on the crystal quality as it is evaluated by parallel plane polariscope and Fizeau interferometer. The experimental findings indicate that the time duration of the shocks has more undesirable influence on the crystal quality than the intensity of shocks. Duration of the shocks could make the crystal not suited for laser applications.

► Water flow rate fluctuations of cooling system are known as a kind of thermal shock.
► Duration and intensity of the shocks have different effects on the crystal quality.
► Large duration shocks decrease the crystal quality with the order of 10 times.
► High intensity shocks decrease the crystal quality with the order of 6 times.
► Large duration shocks make the crystal quality not suited for laser applications.