A variant of the technique known as the horizontal directional solidification method (HDSM) developed by Khachik Bagdasarov (Russian : Хачик Багдасаров) starting in the 1960s in the Soviet Union. It uses a flat-bottomed crucible made out of molybdenum with short sidewalls rather than an enclosed ampoule, and has been used to grow various large oxide crystals including Yb:YAG (a laser host crystal), and sapphire crystals 45 cm wide and over 1 meter long. The quality of the crystals grown by HDSM differs from ones grown by the Czochralski method.