Current State of Knowledge

Two major directions of nanospectroscopy research are geared towards developing high-resolution measurement techniques, and towards applying these techniques for gaining physical, chemical or biological information at the nanoscale. Over the last few decades, optical spectroscopy has managed to reach sub-wavelength spatial resolution in combination with sub-wavenumber spectral accuracy and simultaneous topographic mapping. Time-resolution has been pushed towards femtosecond pulses, offering time-resolved spectra with high signal-to-noise ratio. Currently, confocal and time-resolved fluorescence, transient absorption, and surface- and tip-enhanced Raman spectroscopy, as well as dark-field scattering and absorption spectroscopy are applied to probe the spectral features of objects with high spatial, spectral, and/or temporal resolution. Nanospectroscopy allows for monitoring material properties, chemical reactions, or physical effects down to the single molecule level and a spatial resolution below 10 nm. The main systems that nanospectroscopy is currently applied to are optical nanoantennas, quantum dots / nanocrystals, single molecules / fluorophores, surfaces of material blends, and biological systems / cells.

Current research programs within the EU framework are aimed at employing nanospectroscopy for high-sensitivity biosensing, ultra-high resolution imaging for medicine and biology, applying theses techniques to new areas of application like lanthanides and actinides (the f-elements) or geological samples, at improving large-scale application, reproducibility, and data analysis routines, devising calibration standards for Raman spectroscopy, and at improving light sources and filters. Given the considerable equipment requirements of nanospectroscopy, research is mostly confined to Europe, the USA, and parts of Asia. European and US research are competing e.g. in the fields of nanospectroscopic sensing and high-resolution techniques, with many strong groups located in Europe. Many leading nanospectroscopic equipment vendors with strong R&D activities are based within Europe, but have strong competition in their US counterparts. Thus, the synergistic efforts within the COST Action will push European competitiveness in a future key technology.

The present Action will expand the range of systems that are investigated by nanospectroscopic means, using nanofabrication and molecular engineering approaches to devise novel hybrid composites and devices. It will bring innovation by evolving existing techniques to further improve their signal intensity, contrast, sensitivity, and robustness. State-of-the-art optical nanospectroscopy will specifically be addressed to the global problems of energy efficiency, light harvesting, and health care.