Subwavelength spectoscopy, exciton supertips and mesoscopic light-matter interactions

Abstract

Subwavelength optical light sources and probes are leading to new devices, technologies and techniques such as near-field microscopy, spectroscopy and biochemical sensing. We have prepared nanometer light sources as small as 40 nm in diameter and exciton sources that are even smaller by adding various inorganic and organic crystals and molecularly doped polymers to micropipettes and nanofabricated fiber-optic tips. We demonstrate subwavelength spectroscopy with highly spatially resolved flourescence spectral of nanocrystals (perylene) in polymeric glasses (PMMA). We also demontrate an interfacial Kasha (external heavy-atom) effect on a perylene nanocrystal surface. We give results on near-field optics and energy transfer at interfaces of nanocrystals (anthracene or diphenyl-anthracene) and dyes (rhodamine B) or dyes embedded in Langmuir-Blodgett films. We discuss the rise of new phenomena when the light source and the sample form a combined mesoscopic system, with subsequent quantum optics effects.