Kao Mung-Chung, Pegoraro Adrian F, Kingston David M, Stolow Albert, Kuo Wen-Chuan, Mercier Patrick H J, Gogoi Ankur, Kao Fu-Jen, Ridsdale Andrew
Institute of Biophotonics, National Yang Ming University, 155, Sec. 2, Li-Nong St., Taipei, 112, Taiwan.
Department of Physics, University of Ottawa, 25 Templeton Ave., Ottawa, ON, K1N 6N5, Canada.
Sci Rep. 2018 Nov 16;8(1):16917. doi: 10.1038/s41598-018-34779-9.
Multi-modal nonlinear optical (NLO) microscopy, including stimulated Raman scattering (SRS) and second harmonic generation (SHG), was used to directly image mineralogical features of economic ore and rock samples. In SRS/SHG imaging, ore samples generally require minimal preparation and may be rapidly imaged, even in their wet state. 3D structural details, at submicron resolution, are revealed tens of microns deep within samples. Standard mineral imaging based on scanning electron microscopy (SEM), with elemental analysis via energy dispersive X-Ray spectroscopy, was used to independently validate the mineral composition of the samples. Spatially-resolved SRS from dominant Raman-resonant bands precisely maps the locations of specific minerals contained within the samples. SHG imaging reveals locally non-centrosymmetric structures, such as quartz grains. Competing absorption and nonlinear scattering processes, however, can reduce contrast in SRS imaging. Importantly, the correlation between standard electron microscopy and multi-modal NLO optical microscopy shows that the latter offers rapid image contrast based on the mineral content of the sample.
多模态非线性光学（NLO）显微镜，包括受激拉曼散射（SRS）和二次谐波产生（SHG），被用于直接成像经济矿石和岩石样品的矿物学特征。在SRS/SHG成像中，矿石样品通常只需极少的制备，甚至在其湿润状态下也可快速成像。在亚微米分辨率下，样品内部数十微米深处的三维结构细节得以显现。基于扫描电子显微镜（SEM）的标准矿物成像，通过能量色散X射线光谱进行元素分析，被用于独立验证样品的矿物成分。来自主要拉曼共振带的空间分辨SRS精确地绘制了样品中特定矿物的位置。SHG成像揭示了局部非中心对称结构，如石英颗粒。然而，竞争性的吸收和非线性散射过程会降低SRS成像中的对比度。重要的是，标准电子显微镜与多模态NLO光学显微镜之间的相关性表明，后者基于样品的矿物含量提供快速的图像对比度。
