Observation of interdot correlation in single pair of electromagnetically coupled quantum dots

Abstract

The interdot correlation in a single pair of InAs∕GaAs barrier-coupled quantum dots (QDs) is investigated by microphotoluminescence spectroscopy, in which each QD is individually excited at unique energy levels. Surprisingly, we observe an anomalous increase in the luminescence intensity when the two QDs are excited simultaneously. This remarkable finding can be interpreted in terms of the electromagnetic coupling between QDs with thick barrier layers.

Self-assembly of laterally aligned GaAs quantum dot pairs

“…Specifically, the wavefunctions of the carriers confined in each QD of the QD pair (QDP) begin to overlap, resulting in an efficient carrier tunneling [1,2], and the wavefunctions may become admixed to form molecular orbital states. Moreover, resonance in the optical transition energies leads to the formation of a coupled QDP via dipole-dipole interactions [3,4,5]. Proposals for using such a coupling in quantum information processing have been brought forth [6,7].…”

“…Proposals for using such a coupling in quantum information processing have been brought forth [6,7]. To this end, various semiconductor QDPs have been fabricated and studied, such as coupled QDs grown by cleaved edge quantum well overgrowth [1], vertically-aligned QDs grown by StranskiKrastanow epitaxy incorporating an indium-flush procedure [2,4], and interface QDs formed in a quantum well [3]. In this work we demonstrate the fabrication of self-assembled, laterally aligned GaAs/Al 0.27 Ga 0.73 As QDP structures by droplet epitaxy: Droplet epitaxy is a nonconventional growth technique for the self-assembly of high quality nanostructures with lattice-matched materials, making possible the growth of nanostructures with various structural characteristics, such as QDs [8,9,10], quantum rings (QRs) [11], and concentric double QRs [12,13].…”

Creation of entangled states in coupled quantum dots via adiabatic rapid passage

“…Thus the scheme could be implemented using two stacked (vertical) quantum dots at a distance of few nanometers, coupled by Förster energy transfer, but without single-particle tunneling. Such conditions can be achieved in InAs/GaAs coupled quantum dots 32,33 .…”

Nanophotonic Devices Based on Semiconductor Quantum Nanostructures

“…Moreover, each PL group consists of two peaks separated by 2-5 meV, where lower-and higherenergy peaks are indicated as Xa Xb and X2a X2b , respectively. The measurement of spin-selective optical excitation revealed that X2a and X2b peaks originate from excitons with a p-like hole excited state [45]. In contrast, Xa and Xb peaks originate from excitons with an s-like hole ground state because wavefunctions of a hole are not coupled with the neighboring QD as a consequence of the large effective mass of the hole, which leads to a small energy-level separation [45].…”

“…In PL excitation measurements of a CQD system, we ob- served inherent excited states of Ea = 1.3231 eV and Eb = 1.3392 eV for |01> and |10> states, respectively [43], [45]. Thus, the creation of excitons of |01> and |10> states can be controlled individually using two laser sources.…”