Short-range plasmon guides, resonators and antennas imaged by non-linear photoemission electron microscopy

Abstract : The exploitation of plasmonic local field enhancements to promote the local interactions between matter and optical fields motivates numerous researches. The objectives are to understand the mechanisms of plasmon-mediated interactions, and to realize molecularly- or atomically-precise nano-structures favouring such phenomena. We have developed a local-probe-free experiment (M-PEEM [1]) to map the electromagnetic field at the nanoscale close to metal structures. The analysis of the optical response of various metal nano-objects shows evidences of the excitation of so-called “short-range” propagative modes, strongly coupled to a metal nano-wire and highly localized around it at subwavelength scales.[2] After a detailed study of the characteristics of these modes, we have been able to design specific metal nano-objects exhibiting diverse functions such as antenna and local field enhancements. These model systems also gave new insights in the enhanced molecule-field interactions observed in the insulating gap of a scanning tunneling microscope [3-7]