An Honglin, Fleming Simon
Opt Express. 2005 May 2;13(9):3500-5. doi: 10.1364/opex.13.003500.
The spatial distribution of second-order nonlinearity in thermally poled optical fibers was characterized by second-harmonic microscopy. The second-order nonlinearity was found to be confined to a thin layer close to the anode surface and progressed further into the silica as the poling time increased. Position uncertainty of the anode metal wire was observed to have an effect, as the nonlinear layers were found not always symmetrically located around the nearest points between the anode and cathode. Optical microscopy results were obtained on etched poled fiber cross-sections and compared with those from second-harmonic microscopy.
通过二次谐波显微镜对热极化光纤中二阶非线性的空间分布进行了表征。发现二阶非线性局限于靠近阳极表面的薄层中，并且随着极化时间的增加，进一步向二氧化硅内部发展。观察到阳极金属丝的位置不确定性有影响，因为发现非线性层并不总是围绕阳极和阴极之间最近点对称分布。在蚀刻的极化光纤横截面上获得了光学显微镜结果，并与二次谐波显微镜的结果进行了比较。
