Horizontally directed crystallization (HDC) is one of most effective methods for the obtaining of large-size sapphire windows for aerospace engineering and transparent armour, laser and scintillation crystals. 
 Studied in the present work were the conditions for the growth of sapphire crystals with rectangular parts measuring 350×500×40 mm³ and large-size Ti:sapphire crystals by HDC method in reducing gaseous medium (CO+Н₂). The structural, optical and laser characteristics of these crystals were investigated.
The distribution of the temperature fields in the crystals and the thermal convection in the melt were simulated in the frame of a two-dimensional model.  The regions of non-uniform distribution of the thermal and stress fields in the crystals were established. The change of the density of dislocations and their distribution in the crystal bulk after making corrections of the technological growth conditions were considered. This made it possible to optimize the thermal conditions for the growth of large-size sapphire and Ti:sapphire crystals by the method of HDC.  
The conditions for the growth of Ti:sapphire crystals with high optical homogeneity were established. Activator striation was shown to be essentially reduced by proper choice of the thermal and convective conditions in the melt. The investigation of the laser characteristics testifies that the method of HDC is promising for the growth of  wide-aperture Ti:sapphire crystals.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/28947 must be provided.

1. New Ca₁₀Li(VO₄)₇ laser host: growth and properties
2. Analysis of dielectric properties of PbMoO₄:Nd and PbWO₄:Nd single crystals
3. Invstigation of the growth of LiH₂PO₄ crystals from phosphate solutions
4. Changes in morphology and element composition of nitrided sapphire substrates at layer-by-layer polishing
5. Morphology of the surface of modified  AlN/sapphire substrates obtained by thermochemical nitridation method
6. Impact of incorporation of TiO₂ and Al₂O₃•nH₂O metal oxide nanoparticles on bulk properties of KDP crystals
7. Optical ceramics based on cubic refractory oxides via vacuum sintering
8. Growth and characterization of dye doped KH₂PO₄ crystals for nonlinear optical applications