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Growth of large-size sapphire and Ti:sapphire crystals with high optical and structural characteristics by HDC method

Viacheslav M. Puzikov 1Georgyi Adonkin Viacheslav Baranov Aleksander Budnikov Leonid Gryn 1Sergii V. Nizhankovskyi 1Natalia Sidelnikova Alina Tanko 

1. Institute for Single Crystals NAS of Ukraine (ISC), 60 Lenin Ave., Kharkov 61001, Ukraine

Abstract

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.

 

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Related papers

Presentation: Oral at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, General Session 2, by Leonid Gryn
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17

Submitted: 2013-03-27 13:45
Revised:   2013-04-01 12:45