Demonstration of a nanophotonic NOT-Gate using near-field optically coupled quantum dots

We demonstrate, for the first time, operation of a nanometric optical NOT-gate using CuCl quantum dots coupled by an optical near-field interaction. The device size was smaller than 20nm and its operation energy was much lower than that of a conventional photonic device. Toward an actual nanophotonic device, we discuss the possibility of coupled InAlAs quantum dots. Double-layer InAlAs quantum dots were prepared using MBE. On the near-field luminescence spectroscopy, a luminescence peak from a single InAlAs quantum dots was observed for the first time. We show that the sample has great potential for a nanophotonic device.