Single carbon nanotubes as ultrasmall all-optical memories

Performance improvements are expected from integration of photonic devices into information processing systems, and in particular, all-optical memories provide a key functionality. Scaling down the size of memory elements is desirable for high-density integration, and the use of nanomaterials would allow for devices that are significantly smaller than the operation wavelengths. Here we report on all-optical memory based on individual carbon nanotubes, where adsorbed molecules give rise to optical bistability. By exciting at the high-energy tail of the excitonic absorption resonance, nanotubes can be switched between the desorbed state and the adsorbed state. We demonstrate reversible and reproducible operation of the nanotube optical memory, and determine the rewriting speed by measuring the molecular adsorption and desorption times. Our results underscore the impact of molecular-scale effects on optical properties of nanomaterials, offering new design strategies for photonic devices that are a few orders of magnitude smaller than the optical diffraction limit.Comment: 8 pages, 6 figure

Field excursion to enhance coastal and environmental engineering capacities of engineers in administrative positions

The capacity building of coastal administrators is essential for sustainable coastal zone management. In order to enhance the ability of trainees in coastal and environmental engineering, the College of Land, Infrastructure, Transport and Tourism of the Japanese Government has carried out annual field excursions to Kujukuri Beach, a typical sandy beach in central Japan for comprehensively learning about real phenomena occurring on the beach and in the hinterland. This paper describes the excursion in 2011, in which 20 trainees participated. The importance of learning through the field excursions to coasts is discussed