为探明两种不同大小的海水珍珠的内部结构差异, 利用一种新型扫频光学相干层析(OCT)成像系统和Raman光谱仪, 无损分析了中国南珠和南洋珠两类海水珍珠。Raman光谱分析表明, 这批海水珍珠主体物相皆为文石, 未检测到人工有机染色物和添加物。基于该OCT成像系统的测量和图形处理功能, 对这批海水珍珠珠层厚度进行了快速、有效的测量, 并根据珠层厚度, 将其质量等级分成五等。对比分析了这批海水珍珠样品的厚度与直径, 除少数样品外, 这批海水珠层厚度与珍珠直径呈弱正相关。此外, 通过OCT二维图像的纹理特征, 对这批海水珍珠的珍珠层、过渡层、珠核层组织的均匀性等进行了归类和评估。OCT成像技术可为珍珠的珠层厚度和均匀性质量分级提供重要依据。

To ascertain the inner structure diversity of the two different size sea pearls, some sea pearls including south pearls of China and south sea pearls were non-destructively analyzed by a new swept-source optical coherence tomography (OCT) technique and Raman spectroscopy. The Raman spectrum analysis results indicate that the phases of the nacre of all sea pearls are aragonite. Any artificial organic dye and additive were not found. The nacre thicknesses were speedily and effectively determinated based on the measuring function and graph manipulation function of this OCT technique. On the basis of the nacre thickness data, these sea pearls can be classified into five grades. The thickness and the diameter of the pearls were comparatively studied. The thicknesses of most of sea pearls have weak positive correlation with the diameters except several ones. In addition, according to the texture characteristics of OCT 2D images, the quality uniformity of nacre, transition layer and nucleus were classified and evaluated. The OCT technique could provide significant evidence for grade classification for nacre thickness and quality uniformity of pearls.