Optical cleaning of congruent lithium niobate crystals
Optical cleaning of congruent lithium niobate crystals
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DOI：
10.1038/nphoton.2009.142
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发表时间：
2009-09-01
期刊：
影响因子：
35
通讯作者：
Buse, K.
中科院分区：
文献类型：
--
作者：
Koesters, M.;Sturman, B.;Buse, K.
铌酸锂（LiNbO3），也被称为“光子学的硅”，在先进光子学和非线性光学中是不可或缺的（1-10）。然而，对于许多应用来说，这种材料受到过渡金属的污染太严重，而过渡金属在百万分之一的水平上是不可避免的。这些杂质作为光电子的来源和陷阱，造成光学损伤，阻碍了LiNbO3的可用性。因此，已经作出努力，以摆脱光激发电子（11,12）。这里我们介绍一种称为“光学清洗”的方法。我们从理论上和实验上证明，如果材料被加热到中等温度，允许离子迁移并保持电荷中性，适当移动的光束将光激发电子像刷子一样推出照射区域，并提供指数清洁。这保证了目前技术无法达到的净化水平。
Lithium niobate (LiNbO3), also called the 'silicon of photonics', is indispensable in advanced photonics and nonlinear optics(1-10). For many applications, however, the material is too polluted by transition metals, which are unavoidable at the parts per million level. These impurities serve as sources and traps for photoelectrons, causing optical damage and hampering the usability of LiNbO3. Efforts have therefore been made to get rid of the photoexcitable electrons(11,12). Here we introduce a method termed 'optical cleaning'. We show theoretically and experimentally that, if the material is heated to moderate temperatures, allowing ions to migrate and to maintain charge neutrality, an appropriately moving light beam pushes photoexcitable electrons out of the illuminated region like a brush, and provides exponential cleaning. This promises purification levels that are beyond the reach of current technologies.