ABSTRACT
One of the most important issues of nanophysics is near- eld electromagnetic interaction between nanometer-sized electronic systems, which generates correlation between electronic systems and governs excitation transfer and the resulting functions of nanodevices and nanosystems (Hori 2001). As the nature of strongly coupled elds plus matter system, near- eld interactions generate complicated space-time correlation depending on the shape, size, and layout of material systems and bring us with a wide variety of novel functions useful for the exploration of nanoscience and nanotechnology. e strong space-time correlation also reveals basic problems involved in electromagnetic interactions in nanometer scales, such as di culties in de ning electromagnetic properties of matter in mean- eld regime, in implementing unidirectional signal transport processes, and in considering electromagnetic causality related to near- eld interactions. e key study to investigate these problems lies in the elds of near- eld optics and nanophotonics, because relatively large optical wavelengths enable us to identify near- eld phenomena from those related to light wave propagation (Ohtsu and Hori 1999). A rapid progress in near- eld optics and nanophotonics has been made in the last two decades based on the developments of nano-fabrication techniques, scanning probe microscopy, and precision laser spectroscopy, and brought us with both the theoretical and the experimental backgrounds enough to study the dissipation processes and hierarchy properties of near- eld interactions in relation to innovation in functional devices and systems.
