Near-Field IR Imaging

Contribution of the University of Jyväskylä to the infrastructure includes acquisition of an instrument for spectroscopic studies and imaging of materials down to 10 nm resolution. The instrument will be unique to Finland, one of the few examples in the Nordic countries, and also uncommon in the rest of Europe or North America.

Near-field-based spectroscopy and imaging at nanoscale resolution is significant because the characteristic scale for functional biological molecules and electronic devices is on the order of 10 nm. Thus, it is of utmost importance to extend the spatial resolution of optical characterization tools to this scale. The equipment for nanospectroscopy consists of scattering-type near-field optical microscopy (SNOM) which is based on enhancement of the electromagnetic field close to a nanotip. Tip-enhanced detection can be coupled with a wide variety of spectroscopic techniques spanning spectral range from terahertz (THz) to ultraviolet (UV). This broad range enables a multitude of investigations, e.g. graphene plasmonics in THz range, nanoscale chemical analysis via vibrational spectroscopy (nano-Fourier transform IR (FTIR)), plasmonics and optical characterisation at UV/Visible range, and solvent-solute interactions in the interfaces with the THz-detection. In the material sciences, nanoscale material segregation, defects, strain and impurities can be studied. In life sciences, IR spectra of individual protein complexes, cell compartments, cell extracts, or lipid bilayers, to name a few, can be measured. In addition, the system can be combined with ultra-fast laser systems. This allows detection of chemical reactions and dynamics of molecular interactions during molecular lifetimes, from femtoseconds to milliseconds, as demonstrated for ensembles.