Yoko Sekine

Demonstration of modulatable optical near-field interactions between dispersed resonant quantum dots

We experimentally demonstrated the basic concept of modulatable optical near-field interactions by utilizing energy transfer between closely positioned resonant CdSe/ZnS quantum dot (QD) pairs dispersed on a flexible substrate. Modulation by physical flexion of the substrate changes the distances between quantum dots to control the magnitude of the coupling strength. The modulation capability was qualitatively confirmed as a change of the emission spectrum. We defined two kinds of modulatability for quantitative evaluation of the capability, and an evident difference was revealed between resonant and non-resonant QDs.

Demonstration of Modulatable Nanophotonics based on modulatable optical near-field interactions between dispersed quantum dots

Optical near-field interactions exhibit high-efficiency energy transfer between closely positioned nanometric materials, and the subsequent optical response induced by the transfer can be controlled by modulating the spatial distribution. We experimentally demonstrated the basic concept of such modulatable optical near-field interactions, termed Modulatable Nanophotonics, with quantum dots dispersed on a flexible substrate.

Nanophotonic hierarchical hologram: hierarchical information processing and nanometric data retrieval based on nanophotonics

A nanophotonic hierarchical hologram works in both optical far-fields and near-fields, the former being associated with conventional holographic images, and the latter being associated with the optical intensity distribution based on a nanometric structure that is accessible only via optical near-fields. In principle, a structural change occurring at the subwavelength scale does not affect the optical response functions, which are dominated by propagating light. Therefore, the visual aspect of the hologram is not affected by such a small structural change on the surface, and retrieval in both fields can be processed independently. We propose embedding a nanophotonic code, which is retrievable via optical near-field interactions involving nanometric structures, within an embossed hologram. Due to the one-dimensional grid structure of the hologram, evident polarization dependence appears in retrieving the code. Here we describe the basic concepts, numerical simulations, and experimental demonstrations of a prototype nanophotonic hierarchical hologram with a nanophotonic code and describe its optical characterization.