Feb 17 2021
Images provide information - what we can observe with our own eyes enables us to understand. Constantly expanding the field of perception into dimensions that are initially hidden from the naked eye, drives science forward.
如今，越来越强大的显微镜使我们能够看到生物体的细胞和组织，微生物和无生命的自然。但是，即使是最好的显微镜也有限制。"To be able to observe structures and processes down to the nanoscale level and below, we need new methods and technologies,"耶拿大学的光学与量子电子研究所的Silvio Fuchs博士说。这特别适用于材料研究或数据处理等技术领域。亚博网站下载"These days, electronic components, computer chips or circuits are becoming increasingly small,"添加了Fuchs。他现在与同事一起开发了一种方法，可以显示和研究如此微小，复杂的结构，甚至可以“看到”它们而不会破坏它们。在本期《科学杂志》中”Optica", the researchers present their method - Coherence Tomography with Extreme Ultraviolet Light (XCT for short) - and show its potential in research and application.
光穿透样品，并由内部结构反射
该研究的主要作者解释说，成像程序基于光学相干断层扫描（OCT），该研究已在眼科中建立了多年。"These devices have been developed to examine the retina of the eye non-invasively, layer by layer, to create 3-dimensional images."At the ophthalmologist, OCT uses infrared light to illuminate the retina. The radiation is selected in such a way that the tissue to be examined does not absorb it too strongly and it can be reflected by the inner structures. However, the physicists in Jena use extremely short-wave UV light instead of long-wave infrared light for their OCT.“这是由于我们想要成像的结构的大小，”费利克斯·威斯纳（Felix Wiesner）说。为了查看只有几纳米的结构尺寸的半导体材料，需要只有少量纳米的光线。亚博网站下载
Nonlinear optical effect generates coherent extremely short-wave UV light
Generating such extremely short-wave UV light (XUV) used to be a challenge and was almost only possible in large-scale research facilities. Jena physicists, however, generate broadband XUV in an ordinary laboratory and use what are called high harmonics for this purpose. This is radiation that is produced by the interaction of laser light with a medium and it has a frequency many times that of the original light. The higher the harmonic order, the shorter the resulting wavelength."In this way, we generate light with a wavelength of between 10 and 80 nanometres using infrared lasers,"explains Prof. Gerhard Paulus, Professor of Nonlinear Optics at the University of Jena.“像辐照的激光一样，所得的宽带XUV光也相干，这意味着它具有激光样性能。"
在当前论文中描述的工作中，物理学家将硅中的纳米层结构暴露于相干XUV辐射，并分析了反射的光。硅样品在不同深度的其他金属（例如钛或银）中包含薄层。由于这些材料与硅具有不同的反亚博网站下载射特性，因此可以在反射辐射中检测到它们。该方法是如此精确，以至于不仅可以以纳米的精度显示小样品的深层结构，而且由于反射行为的不同，还可以精确地确定样品的化学组成，最重要的是- 严重的方式。“这使得连贯性断层扫描是检查半导体，太阳能电池或多层光学组件的有趣应用，”保罗说。它可用于在此类纳米材料的制造过程中进行质量控制，以检测内部缺陷或化学杂质。亚博网站下载
Original publication:威斯纳F.等。使用极端紫外线层析成像对纳米层的物质特定成像，Optica(2021),https://www.osapublishing.org/optica/fulltext.cfm-uri=optica-8-2-230&id=447633
来源：http://www.uni-jena.de