LMI Seminar: Non-invasive nanoscale cross-sectional XUV imaging

Abstract:

I will discuss nanoscale imaging in the extreme ultraviolet (XUV) spectral region using high-harmonics produced by femtosecond laser radiation. As opposed to other XUV imaging approaches, our scheme can exploit the entire high-harmonic spectrum. In fact, our method is the XUV incarnation of optical coherence tomography, albeit vastly differently implemented due to the challenges of XUV optics. Thus, it is referred to as XUV coherence tomography, XCT.

A particularly relevant application of XCT for the spectral range up to 100 eV are silicon-based samples. We have demonstrated depth resolutions of 20 nm and very high sensitivities. Buried oxide layers of a thickness of a few nanometers could be detected as well as buried monolayers of graphene. It is even possible to identify the material encapsulated in silicon and determine also properties like layer roughness without destroying the sample. A unique perspective is ultrafast imaging