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High‐temperature infrared and dielectric properties of large sapphire crystal for seeker dome application
Author(s) -
Wang Guigen,
Zhang Mingfu,
Han Jiecai,
He Xiaodong,
Zuo Hongbo,
Yang Xinhong
Publication year - 2008
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.200711066
Subject(s) - sapphire , dielectric , infrared , materials science , transmittance , crystal (programming language) , microwave , dome (geology) , atmospheric temperature range , optics , optoelectronics , geology , thermodynamics , telecommunications , physics , laser , paleontology , computer science , programming language
In this paper, large‐sized (∅230 mm × 210 mm, 27.5 kg) sapphire was successfully grown by SAPMAC (sapphire growth technique with micro‐pulling and shoulder‐expanding at cooled center) method; and hemisphere dome (140 mm diameter, 5 mm thickness) was fabricated from as‐grown boule. Also, its high temperature infrared transmission (2∼7 µm, 20–800°C) and microwave dielectric properties (8–16.5 GHz, 30–1300°C) were investigated. The experimental results show that sapphire crystal exhibits high infrared transmittance (3 μm, 80–86%), essentially negligible dielectric loss (4.9×10 ‐5 –3.7×10 ‐4 ), but fairly high dielectric constants (ε=9.4–12.5) in the temperature range of 30–1300°C. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)