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Proceedings Paper

Optical homogeneity and growth defects in sapphire crystals grown by different methods
Author(s): C. Logofatu; I. Licea; N. Mincu; Cristiana E. A. Grigorescu
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Paper Abstract

To investigate the optical homogeneity of crystals some methods based on the analysis of the laser beams interacting with a sample have been recently proposed. The emergent beam is acquired by a data acquisition/image processing system which offers the possibility for both local and global analysis of the sample. Combined with microscopy techniques these methods enable the study of submicron defects such as scattering centers, clusters of punctual defects, microcracks. A map of the absorption coefficient (alpha) equals(alpha) (x,y) can be obtained by recording the transmitted light when scanning the sample with the laser beam. This result is particularly useful for determining some growth parameters because spatial variation of the absorption coefficient is a consequence of thermal oscillations in the crystallization system. Our paper is a short study on the optical homogeneity of sapphire crystals grown by different techniques as related to the particular defects induced by the growth process. Laser beam analysis has been mainly employed to characterize the samples. The results provide important information on the dynamics of the crystallization interface during the growth processes, on the number and types of growth defects, foreign phase precipitations, inclusions, thermal stress, etc., which may help with optimization of the growth parameters.

Paper Details

Date Published: 29 June 2001
PDF: 9 pages
Proc. SPIE 4430, ROMOPTO 2000: Sixth Conference on Optics, (29 June 2001); doi: 10.1117/12.432821
Show Author Affiliations
C. Logofatu, National Institute for Laser, Plasma and Radiation Physics (Romania)
I. Licea, Univ. of Bucharest (Romania)
N. Mincu, National Institute of Research and Development for Optoelectronics (Romania)
Cristiana E. A. Grigorescu, National Institute of Research and Development for Optoelectronics (Romania)

Published in SPIE Proceedings Vol. 4430:
ROMOPTO 2000: Sixth Conference on Optics
Valentin I. Vlad, Editor(s)

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