Advanced analysis of domain walls in Mg doped LiNbO3 crystals with high resolution OCT.
Advanced analysis of domain walls in Mg doped LiNbO3 crystals with high resolution OCT.
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DOI：
10.1364/oe.25.014871
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发表时间：
2017-06
期刊：
影响因子：
3.8
通讯作者：
L. Kirsten;A. Haußmann;C. Schnabel;Sebastian Schmidt;P. Cimalla;L. Eng;E. Koch
中科院分区：
文献类型：
--
作者：
L. Kirsten;A. Haußmann;C. Schnabel;Sebastian Schmidt;P. Cimalla;L. Eng;E. Koch
铁电介质中的畴壁结构是人们非常感兴趣的，因为这种材料用于倍频器和其他应用。我们表明，DWs的结构可以很好地通过高分辨率光学相干断层扫描（OCT）可视化。虽然锂的高群折射率允许分辨率远优于1 μm，但大的色散会使图像模糊，必须进行补偿。因此，我们开发了一种基于最大化DW强度的自适应色散补偿算法。通过测量一组DW，DW的平均周期可以以小于10 nm的精度测量，区分仅具有30 nm不同周期的样品。通过分析DW内的峰位置、振幅和相移，我们能够确定DW中仅50 nm的阶跃。此外，还可以显示出扇形倍频器中各波的倾斜走向。因此，我们的结论是，OCT是能够提供有价值的信息的畴壁的结构在周期性极化的锂钛酸盐（PPLN）。
The structure of domain walls (DW) in ferroelectric media is of great interest as this material is used for frequency doublers and other applications. We show that the structure of the DWs can nicely be visualized by high resolution optical coherence tomography (OCT). While the high group refractive index of lithium niobate allows a resolution much better than 1 µm, the large dispersion can blur the image and has to be compensated. Therefore, we developed an adaptive dispersion compensation algorithm based on maximizing the intensity of the DWs. By measuring a group of DWs, the mean period of the DWs could be measured with an accuracy of less than 10 nm differentiating samples with only 30 nm distinct periods. By analyzing the peak position, amplitude and phase shift within a DW, we were able to determine steps in the DW of only 50 nm. Furthermore, the inclined course of the DWs in a fan-shaped frequency doubler could be displayed. Therefore, we conclude that OCT is able to provide valuable information about the structure of domain walls in periodically poled lithium niobate (PPLN).