Sapphire fibers grown from the melt by the EFG technique: dependence of the impurity distribution on temperature and surface tension gradients

Thomas F. George; Liliana Braescu

doi:10.1117/12.793279

25 August 2008 Sapphire fibers grown from the melt by the EFG technique: dependence of the impurity distribution on temperature and surface tension gradients

Thomas F. George, Liliana Braescu

Author Affiliations +

Proceedings Volume 7056, Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications II; 705603 (2008) https://doi.org/10.1117/12.793279
Event: Photonic Devices + Applications, 2008, San Diego, California, United States

Abstract

A stationary 2D axis-symmetric model able to evaluate the impurity distribution is developed by the finite element method for single-crystal sapphire fibers grown from the melt by the edge-defined film-fed growth (EFG) technique. The computations are carried out for two cases-one where the buoyancy is taken into account and the other where the buoyancy is neglected-using different vertical temperature gradients kg in the furnace. The dependence of the impurity distribution on kg and the Marangoni numbers Ma corresponding to the different surface tension gradients dγdT is analyzed. Computations reveal critical Marangoni numbers Ma_c determined by the fluid flow behavior, and that a smaller k_g assures the best homogeneity of the crystal over a wide range of d_γ/dT.

Citation Download Citation

Thomas F. George and Liliana Braescu "Sapphire fibers grown from the melt by the EFG technique: dependence of the impurity distribution on temperature and surface tension gradients", Proc. SPIE 7056, Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications II, 705603 (25 August 2008); https://doi.org/10.1117/12.793279

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available