Infrared spectroscopy across scales in length and time at BESSY II

Abstract: The infrared beamline at BESSY II storage ring was upgraded recently to extend capabilities of infrared microscopy. The end-stations available at the beamline are now facilitating improved characterization of molecules and materials at different length scales and time resolution. We report the current outline of the beamline and give an overview of the end-stations available. In particular, presented here are first results obtained with using a new microscope for nano-spectroscopy that was implemented. We demonstrate the capabilities of the scattering-type near-field optical microscope (s-SNOM) by investigation of cellulose microfibrils, representing nanoscopic objects of a hierarchical structure. It is shown that the s-SNOM coupled to the beamline allows to perform imaging with spatial resolution less than 30 nm and to collect infrared spectra from effective volume of less than 30x30x12 $nm^3$. Potential steps for a further optimization of the beamline performance are discussed.