Showing papers by "Nika Akopian published in 2009"
TL;DR: These experiments demonstrate the potential of this system to form a quantum interface between photons and electrons and can prepare a given spin state by tuning excitation polarization or excitation energy.
Abstract: We report exciton spin memory in a single InAs0.25P0.75 quantum dot embedded in an InP nanowire. By synthesizing clean quantum dots with linewidths as narrow as about 30 µeV, we are able to resolve individual spin states at magnetic fields on the order of 1 T. We can prepare a given spin state by tuning excitation polarization or excitation energy. These experiments demonstrate the potential of this system to form a quantum interface between photons and electrons.
95 citations
TL;DR: The study has demonstrated that by directing light along the nanowne axis the authors can access the intrinsic polarization properties of an exciting confined in a QD in a nano wire, thereby introducing a theoretical model that intuitively explains the experimental lickings.
Abstract: The correlation of the polarization of light absorbed that are emitted by a QD embedded in a nanowire with its propagation direction with respect to the nanowire axis are discussed. The study has also demonstrated that by directing light along the nanowne axis we can access the intrinsic polarization properties of an exciting confined in a QD in a nano wire, thereby introducing a theoretical model that intuitively explains the experimental lickings and shows how the polarization dependence in absorption is affected by various parameters such as nanowire diameter. The experiments revealed that the polarization of the absorbed light when directed perpendicular to the nanowire axis, is affected hI the nanowire geometer and is strongly linearly polarized along the nanowire, in consideration with the intrinsic polarization of the nanowire OD. The results also demonstrates the polarization of photons radiated from a Zeeman split exciting in a nanowire QD with the optical path aligned along the nanowire axis as well as perpendicular to the nanowire axis.
37 citations
01 Nov 2009
TL;DR: In this article, the optical properties of InP/InAsP/Asp/InP nanowire quantum dots and single-photon Fourier spectroscopy of an exciton in a single InAsP quantum dot embedded in an InP QD were investigated by excitation power and energy dependencies.
Abstract: We report optical properties of InP/InAsP/InP nanowire quantum dots and single-photon Fourier spectroscopy of an exciton in a single InAsP quantum dot embedded in an InP nanowire The coherent length of the time-averaged emission originating from the single InAsP QD was measured by a Mach-Zehnder interferometer inserted in the photoluminescence path E!ects of fluctuations in surrounding excess charges trapped in the InP nanowire were investigated by excitation power and energy dependencies
13 citations
TL;DR: In this article, optical studies of single InAs quantum dots grown on vicinal GaAs(001) surfaces were conducted and it was shown that InAs layers 1.4 or 1.5 ML are thinner than the critical thickness for Stranski-Krastanov quantum dot formation.
Abstract: We report on optical studies of single InAs quantum dots grown on vicinal GaAs(001) surfaces. To ensure low quantum dot density and appropriate size, we deposit InAs layers 1.4 or 1.5 ML thick, thinner than the critical thickness for Stranski–Krastanov quantum dot formation. These dots show sharp and bright photoluminescence. Lifetime measurements reveal an exciton lifetime of 500 ps. Polarization measurements show an exciton fine structure splitting of 15 μeV and allow to identify the exciton and charged exciton transitions with linewidth as narrow as 23 μeV.
11 citations
TL;DR: In this paper, the authors observed sharp spectral lines at energies which are higher than the bulk GaN band gap, in the photoluminescence and photolumininescence excitation spectra of GaN/AlGaN heterointerfaces grown by molecular beam epitaxy.
Abstract: We observe sharp spectral lines, at energies which are higher than the bulk GaN band gap, in the photoluminescence and photoluminescence excitation spectra of GaN/AlGaN heterointerfaces grown by molecular beam epitaxy. The spectra and their temperature dependence are in accord with the Fermi edge singularity expected for two dimensional electron gas systems. The associated localized hole energy in the AlGaN interface side was extracted directly from the spectra.
7 citations