Fluorescence mapping of oxidation states of Cr ions in YAG crystal fibers

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• 作者：Chen ; Jian-Cheng ; Lo ; Chia-Yao ; Huang ; Kuang-Yao ; Kao ; Fu-Jen ; Tu ; Shih-Yu ; Huang ; Sheng-Lung
• 关键词：42.30.Va ; 42.62.Fi ; 42.70.Hj ; 42.72.Ai ; 71.70.Ch ; A1. Doping ; A1. Optical microscopy ; A2. Laser heated pedestal growth
• 刊名：Journal of Crystal Growth
• 出版年：2005
• 期刊代码：49_00220248
• 类别：ch
• 出版时间：February 1, 2005
• 卷：274
• 期：3-4
• 页码：522-529
• 文件大小：620 K

摘要

We have demonstrated the use of laser scanning confocal microscope for mapping the refractive index as well as Cr³⁺ and Cr⁴⁺ fluorescence in Cr:YAG crystal fibers with 1μm spatial resolution. The corresponding sensitivities for Cr³⁺ and Cr⁴⁺ fluorescence intensities are 1.6×10¹⁷/cm³ and 7.5×10¹⁵/cm³, respectively. The share of Cr⁴⁺ ions in the total Cr concentration is found to be proportional to the ratio of Ca to Cr concentrations. However, only less than 1%of the Ca²⁺ ions become active in charge compensation. The concentration of Cr⁴⁺ ions is higher near the center of the crystal fiber when the core diameter is less than 300μm. In addition, stress-induced striations created near the fiber center disappear when the fiber diameter is smaller than 500μm.