Preparation method and growth equipment of magnesium fluoride crystal

The invention relates to a preparation method and growth equipment of a magnesium fluoride crystal. The growth equipment comprises a furnace cavity, wherein a gas inlet through hole and a gas outlet through hole are respectively arranged above and below the furnace cavity; and an opening used for dredging impurities generated through crystal growth is arranged above the furnace cavity. The preparation method of the magnesium fluoride crystal comprises the following steps of: setting parameters, and introducing a flowing inert gas into the furnace cavity in the preparation process of the magnesium fluoride crystal; starting to increase the temperature to melt magnesium fluoride powder, after the magnesium fluoride powder is completely melted to form a fusant, dredging oxyfluoride, and placing seed crystals to obtain the grown magnesium fluoride crystal. The prepared magnesium fluoride crystal is excellent in optical quality; and the transmittance of @193 nm is not less than 89%.