We present an overview of recent results on optical coherence tomography with the use of extreme ultraviolet and soft X-ray radiation (XCT). XCT is a cross-sectional imaging method that has emerged as a derivative of optical coherence tomography (OCT). In contrast to OCT, which typically uses near-infrared light, XCT utilizes broad bandwidth extreme ultraviolet (XUV) and soft X-ray (SXR) radiation (Fuchs et al in Sci Rep 6:20658, 2016). As in OCT, XCT’s axial resolution only scales with the coherence length of the light source. Thus, an axial resolution down to the nanometer range can be achieved. This is an improvement of up to three orders of magnitude in comparison to OCT. XCT measures the reflected spectrum in a common-path interferometric setup to retrieve the axial structure of nanometer-sized samples. The technique has been demonstrated with broad bandwidth XUV/SXR radiation from synchrotron facilities and recently with compact laboratory-based laser-driven sources. Axial resolutions down to 2.2 nm have been achieved experimentally. XCT has potential applications in three-dimensional imaging of silicon-based semiconductors, lithography masks, and layered structures like XUV mirrors and solar cells.

我们介绍了使用相干断层扫描仪在极紫外和软X射线辐射（XCT）方面的最新研究成果。XCT是一种横截面成像方法，已作为光学相干断层扫描（OCT）的衍生形式出现。与通常使用近红外光的OCT相比，XCT使用宽带宽的极紫外（XUV）和软X射线（SXR）辐射（Fuchs等人，科学通报6：20658，2016）。与OCT一样，XCT的轴向分辨率仅与光源的相干长度成比例。因此，可以实现低至纳米范围的轴向分辨率。与OCT相比，这最多可提高三个数量级。XCT在共路径干涉测量设置中测量反射光谱，以检索纳米尺寸样品的轴向结构。该技术已被同步加速器设施的宽带宽XUV / SXR辐射以及最近基于实验室的紧凑型激光驱动源进行了证明。实验上已经实现了低至2.2 nm的轴向分辨率。XCT在基于硅的半导体，光刻掩模以及XUV反射镜和太阳能电池等分层结构的三维成像中具有潜在的应用。