Controllable and directional growth of Er:Lu2O3 single crystals by the edge-defined film-fed technique

Abstract

The sesquioxide Lu₂O₃ single crystal has enormous potential applications as host material for solid-state lasers operating at high average powers, and its development is limited by the lack of large sized single crystals with high quality. Compared with the traditional Czochralski (Cz) method, the edge-defined film-fed growth (EFG) method, employing a die or a shaper, doesn't make the grown crystal come into contact with the melt in crucible directly during the growth process. Therefore, the growth interface is stable and the serious bottleneck problems of a “w”-shaped isotherm in the Czochralski method could be avoided effectively. Herein, the EFG method may be a promising technique to obtain ultra-high temperature sesquioxide single crystals with a large size, and more importantly, high quality. Accordingly, the sesquioxide Lu₂O₃ single crystal has been grown controllably with an oriented seed by the EFG method for the first time and the EFG method is promoted to an extremely high temperature of 2450 °C. The dimensions of the grown crystal are Φ 25 × 30 mm³, and the difficulties encountered during the crystal growth have been discussed in detail. Furthermore, the quality of the crystal has been evaluated. The optical properties of the grown crystal have been investigated.