Large-scale rare earth doped yttrium barium fluoride single crystal growth method

Abstract

The present invention provides a large-scale rare earth-doped yttrium-barium fluoride crystal growth method. In a heating furnace, {xReF3+(1‑x)YF3}:BaF2=2:1, x=0~100% The polycrystalline material is placed in a crucible, vacuumized, and argon gas is introduced into the heating furnace successively; the heating power is controlled by a temperature controller to melt it, and the liquid surface in the crucible exchanges heat with the gas flow in the furnace to form an axial temperature difference. A radial temperature difference is formed between the crucible wall and the crucible center, causing natural convection of the melt; then the BaY2F8 seed crystal is fixed on the seed rod with a platinum chuck, and the seed crystal is lowered to contact the melt for fluoride crystal growth; when the fluoride crystal When it grows to the set size, start annealing, cool down to room temperature at a cooling rate of 20°C / hour, adjust the rotation speed and heating power until the crystal grows and separate from the melt, and anneal in the crucible to obtain large-sized fluoride crystals . The invention solves the unfavorable growth factors such as poor crystal growth caused by poor fluidity of the fluoride melt, many bubbles in the crystal, and the like.

Description

technical field [0001] The invention belongs to the field of crystal growth, in particular to a rare earth-doped yttrium barium fluoride Re:BaY 2 f 8 Crystal, especially a large-size fluoride single crystal growth method with a single crystal size greater than 50mm. Background technique [0002] In recent years, rare earth-doped upconversion and laser materials have attracted great attention due to their broad application prospects in laser, optical display, atmospheric monitoring, laser remote sensing, imaging, laser medical treatment, and lidar. Rare earth doped yttrium barium fluoride crystal (Re:BaY 2 f 8 , Re: BYF) belongs to the monoclinic crystal system, biaxial crystal. The crystal has low phonon energy (maximum phonon energy 415cm －1 ), the spectral transmission range is wide (0.12-12µm), and the grown crystal has direct output of mid-infrared band laser and high conversion efficiency. It is widely used in infrared solid-state lasers and detection fields. A s...

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Problems solved by technology

However, the disadvantage of this method is that the entire growth process cannot be observed, real-time adjustment cannot be made during the growth process, and the growth cycle is long, requiring harsh growth conditions.

[0005] The temperature gradient method can avoid the complex convection and temperature fluctuation of the solid-liquid interface caused by the interference of the irregular mechanical vibration source, so the quality of the grown crystal and the single crystal rate are better than the crucible drop method, but due to the crystal growth process Completely relying on diffusion transport, the crystal growth is relatively slow, and there is no relative movement between the growing crystal and the temperature field, which limits the height of the crystal; the traditional top seed crystal method grows during the seed crystal rotation and does not pull upward, and the growth cycle is long. At the same time, this method uses a fully enclosed crucible, the entire growth process is invisible, and the heating method uses graphite heating. The crucible is generally a graphite crucible, and graphite volatilization will affect the quality of the grown crystal.

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