Time-resolved investigations on any phase of matter through pump-probe methods involving FELs and laser beams is a new frontier for modern science. The underlying problem for these experiments is the requirement of an accurate spatial and temporal superposition of pump and probe beams on the sample: at the present, this is still a critical procedure, also in term of large time needed going to the detriment of the available beamtime.
Papers
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A computer-generated holograms (CGH) encoding information for light beams carrying orbital angular momentum (OAM) has been developed in collaboration between IOM-CNR and Padua University. The use of a numerical code, based on an iterative Fourier transform algorithm, allowed a phase-only diffractive optical element (PO-DOE) by exploiting a new method based on transmission through high-order spiral phase plates (SPPs). |
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The nanopatterning of the methylammonium lead iodide (MAPbI3) perovskite, a polycrystalline hybrid organic-inorganic semiconductor with very promising perspectives for photovoltaic and optoelectronic applications has been achieved. Nanopatterning of MAI is obtained via Pulsed-NIL technology, an ultrafast version of the thermal nanoimprint lithography (NIL) based on stamps with integrated heaters. By Pulsed-NIL we were able to replicate onto the hybrid perovskite structures with details at the sub-100 nm scale, in spite of its crystalline nature. |
Cell-cell and cell-matrix interactions are essential to the survival and proliferation of most cells, and are responsible for triggering a wide range of biochemical pathways. More recently, the biomechanical role of those interactions was highlighted, showing, for instance, that adhesion forces are essential for cytoskeleton organization. Silicon nanowires (Si NWs) with their small size, high aspect ratio and anisotropic mechanical response represent a useful model to investigate the forces involved in the adhesion processes and their role in cellular development. |
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Minimization of contamination associated with the graphene transfer process from the growth substrate to the device surface is a major requirement for large scale CVD graphene device applications. We performed a polymer-free method of commercial CVD-grown graphene transfer from the initial copper substrate to the silicon device: 15 nm-thick titanium layer replaces completely the polymer (PMMA) film as supporting layer during the transfer process. The approach reduces significantly the level of contaminations for supported and suspended graphene layers. Raman spectroscopy proves the quality of the transferred graphene, while X-ray photoelectron spectroscopy and X-ray absorption spectroscopy were used to assess the amount of the contaminants left by the transfer process. Overall carbon contamination was reduced by a factor 2, while contaminations originating from the metal etching in hydrofluoric acid, namely titanium and fluorine, were absent within the sensitivity of the used techniques. |