EXPERIMENTAL PROCEDURE

The crystal growth experiments are performed in the following manner. A supersaturated solution of KDP powder is prepared in distilled, de-ionized water. The amount of KDP salt to be dissolved is determined from its solubility curve at an average temperature of . The solution is stirred long enough to ensure complete dissolution of the solute. It is filtered using Whatman-100 filter paper to remove residual microscopic particles. The solution is maintained at relatively high temperature for about 4-5 hours using water circulation from the temperature control unit. Subsequently, the solution is cooled by applying a suitable ramp rate, in the present study. When the solution reaches a value right enough for it to become saturated, a KDP seed is introduced into the solution using a thin glass rod. The orientation of the seed crystal is adjusted in such a way that the prismatic faces are placed normal to the direction of the laser beam. Experiments are allowed to run for a considerably longer duration of time in order to allow the growth of large crystals. Precautions are taken to avoid external disturbances and vibrations that may introduce unsteadiness in the flow field. For the experiments discussed below, the crystal size increased from in 60 hours, while preserving high crystal transparency.