Colloquium: dr. Stefan Witte



WN-M607, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam

Seeing the invisible: light-based 3D imaging of opaque nanostructures

dr. Stefan Witte - Advanced Research Center for Nanolithography and Vrije Universiteit Amsterdam

Faculty of Science



Seeing the invisible: light-based 3D imaging of opaque nanostructures

Nanostructures drive the world around us. Every modern electronic device contains integrated circuits and nano-electronics to provide its functionality. Fabricating such nanostructures crucially depends on having the tools to make them visible without destroying them. Modern nanodevices often have complex three-dimensional architectures with small features in all dimensions, and typically contain layers made of metal and/or semiconductor that are fully opaque to visible light. Imaging such 3D structures in a non-invasive way is therefore a major scientific challenge.

In my group at ARCNL we are working on multiple methods aimed at tackling this challenge. An important tool in that respect is computational imaging: this is an elegant approach to microscopy, in which the image formation is achieved using computer algorithms rather than optical components. Computational imaging enables us to go beyond the limits set by typical imaging hardware: we use this concept to extend microscopy to the extreme-ultraviolet and soft-X-ray wavelength range, and to perform hyperspectral and 3D imaging. Furthermore, we are developing imaging methods using ultrafast laser-induced ultrasound pulses, which allow high-resolution imaging and metrology through metal layers and complex opaque multilayer structures.

I will present our recent progress in developing these imaging techniques and the laser technology and computational methods that enable them. Furthermore, I will discuss the prospects of computational imaging for element-sensitive 3D imaging of complex nanostructures in science and industry.