Coupling efficiency of laser beam to multimode fiber

The coupling efficiency of laser beam to multimode fiber is given by geometrical optics, and the relation between the maximum coupling efficiency and the beam propagation factor M-2 is analyzed. An equivalent factor M-F(2) for the multimode fiber is introduced to characterize the fiber coupling capability. The coupling efficiency of laser beam to multimode fiber is calculated in respect of the ratio M-2/M-F(2) by the overlapping integral theory. The optimal coupling efficiency can be roughly estimated by the ratio of M-2 to M-F(2) but with a large error range. The deviation comes from the lacks of information on the detail of phase and intensity profile in the beam factor M-2. (C) 2007 Elsevier B.V. All rights reserved.

Ultrabroad infrared luminescences from Bi-doped alkaline earth metal germanate glasses

We report on ultrabroad infrared (IR) luminescences covering the 1000-1700-nm wavelength region, from Bi-doped 75GeO(2) 20RO-5Al(2)O(3) 1B(2)O(3) (R = Sr, Ca, and Mg) glasses. The full width at half-maximum of the IR luminescences excited at 980 nm increases (315 -> 440 -> 510 nm) with the change of alkaline earth metal (Mg2+ -> Ca2+ -> Sr2+). The fluorescence lifetime of the glass samples is 1725, 157, and 264 mu s when R is Sr, Ca, and Mg, respectively. These materials may be promising candidates for broad-band fiber amplifiers and tunable laser resources.

氧氟碲酸盐玻璃析晶性质的研究

以TeO2-ZnO-ZnF2系统为研究对象，采用差热分析计算分析了玻璃样品的析晶活化能E，并且得出了析晶速率k与温度的关系。结果表明，随着玻璃中氟化物含量的增加析晶速率提高，不利于实现热处理可控析晶过程，氟化物组分引入的含量对制备该系统透明玻璃陶瓷有很大的影响。

《中国双子叶木本植物叶的宏观结构》（英文版）

本书是一部区域性的系统记载植物叶形态的专著，对我国华南地区习见的96科、315属、700多种双子叶木本植物叶的宏观结构，包括：叶形、脉序：1-6级脉、脉岛、盲脉、叶缘脉等形态，逐一分布加以描叙，在各属内列有脉序特征为依据的分种检索表，每种除文字记载外，均附有显示叶形及各级脉序的照片两帧，以便于鉴定。所引用的标本均标明出处，以便查对。此外还附有每种植物的地理分布、习性、生境等资料。这样内容的书在我国尚属首次。目前国内外发表的叶片脉序论著都是专科专属的研究。本书研究记载范围广，资料性较强对研究现代双子叶植物分类系统有重要参考价值，对古植物学研究有很大帮助，对地质工作也有一定的实用意义。全书用英文撰写，更便于各国学者交流参考。