Demonstration of Controlling the Spatiotemporal Dynamics of Optical Near-Field Excitation Transfer in Y-Junction Structure Consisting of Randomly Distributed Quantum Dots

Wataru Nomura,Makoto Naruse,Tadashi Kawazoe,Motoichi Ohtsu,Masashi Aono,Takashi Yatsui,Song-Ju Kim

doi:10.1155/2014/569684

Abstract

Solution searching devices that operate on the basis of controlling the spatiotemporal dynamics of excitation transfer via dressed photon interactions between quantum dots have been proposed. Long-range excitation transfer based on dressed photon interactions between randomly distributed quantum dots is considered to be effective in realizing such devices. Here, we successfully controlled the spatiotemporal dynamics of excitation transfer using a Y-junction structure consisting of randomly dispersed CdSe/ZnS core-shell quantum dots. This Y-junction structure has two “output ends” and one “tap end.” By exciting one output end with control light, we observed increased excitation transfer to the other output end via a state-filling effect. Conversely, we observed reduced excitation transfer to the output ends by irradiating the tap end with control light, due to excitation of defect levels in the tap end. These results show the possibility of controlling the optical excitation transfer dynamics between multiple quantum dots.

Highlights

Light excitation in quantum dots (QDs) generates dressed photons, which are light fields localized in the vicinity of the QDs, giving rise to dressed photon interactions with other nearby matter, as well as excitation energy transfer via these interactions [1]
To show the possibility of controlling the spatiotemporal dynamics of optical excitation transfer based on dressed photon interactions between multiple randomly distributed quantum dots (QDs), we conducted experiments to control excitation transfer using randomly distributed QD structures
Optical excitation incident at the center of this structure was transferred to a QD2 structure serving as an output end located 3–7 μm away, and by irradiating a QD2 structure at another end with control light Pin2, we observed a maximum increase of 7.3 × 10−2

Summary

Introduction

Light excitation in quantum dots (QDs) generates dressed photons, which are light fields localized in the vicinity of the QDs, giving rise to dressed photon interactions with other nearby matter, as well as excitation energy transfer via these interactions [1]. Novel solution searching and decision making devices using a QD array provided with multiple output QDs have recently been proposed [8,9,10]. In these devices, by inputting control signals to the output QDs based on certain rules, the probability of the optical excitation being transferred uniformly to each QD is controlled to obtain a solution. By inputting control signals to the output QDs based on certain rules, the probability of the optical excitation being transferred uniformly to each QD is controlled to obtain a solution In these operations, it is necessary to control the spatiotemporal dynamics of the optical excitation transfer between spatially distributed QDs. The features of these

Methods

Discussion

Conclusion