Line-Focus-Beam Acoustic Microscopy Detection of Variations of Growing Conditions of LiTaO 3 Crystals

• Published in: Japanese Journal of Applied Physics 1999-08, Vol.38 (8B), p.L964, Article L964
• Main Authors: Jun-ichi Kushibiki, Jun-ichi Kushibiki, Tadashi Okuzawa, Tadashi Okuzawa
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.38.L964

Line-focus-beam (LFB) acoustic microscopy is applied to evaluate the homogeneities of optical-grade LiTaO 3 single crystals, pulled along the crystallographic Y axis. Z-cut substrates prepared from three kinds of single crystals with different chemical compositions of 48.0, 48.5, and 49.0 Li 2 O-mol% as the starting materials, and one commercially available optical-grade congruent LiTaO 3 single crystal, are examined by measuring the leaky surface acoustic wave (LSAW) velocities along the Y axis. Using the relationship between the LSAW velocities and chemical compositions obtained from the three crystals, some significant and characteristic velocity variations of 0.54 m/s along the pulling-axis direction and of at most 0.38 m/s along the diameter direction were observed on the congruent specimen surface, corresponding to the chemical composition changes of 0.017 and 0.012 Li 2 O-mol%, respectively. This is the first evidence to signify that the variations are in essence due to changes of the crystal growing conditions during the growth process.