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Rosa BLT, Marçal LAB, Andrade RR, Pinto LD, Rodrigues WN, Souza PL, Pires MP, Nunes RW, Malachias A. Observation of partial relaxation mechanisms via anisotropic strain relief on epitaxial islands using semiconductor nanomembranes. NANOTECHNOLOGY 2017; 28:305702. [PMID: 28675147 DOI: 10.1088/1361-6528/aa78e7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this work we attempt to directly observe anisotropic partial relaxation of epitaxial InAs islands using transmission electron microscopy (TEM) and synchrotron x-ray diffraction on a 15 nm thick InAs:GaAs nanomembrane. We show that under such conditions TEM provides improved real-space statistics, allowing the observation of partial relaxation processes that were not previously detected by other techniques or by usual TEM cross section images. Besides the fully coherent and fully relaxed islands that are known to exist above previously established critical thickness, we prove the existence of partially relaxed islands, where incomplete 60° half-loop misfit dislocations lead to a lattice relaxation along one of the 〈110〉 directions, keeping a strained lattice in the perpendicular direction. Although individual defects cannot be directly observed, their implications to the resulting island registry are identified and discussed within the frame of half-loops propagations.
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Affiliation(s)
- Barbara L T Rosa
- Departamento de Física, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
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2
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Tropp J. A quantum description of radiation damping and the free induction signal in magnetic resonance. J Chem Phys 2013; 139:014105. [DOI: 10.1063/1.4811180] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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3
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Ma Y, Huang M, Ryu S, Bark CW, Eom CB, Irvin P, Levy J. Broadband terahertz generation and detection at 10 nm scale. NANO LETTERS 2013; 13:2884-2888. [PMID: 23692301 DOI: 10.1021/nl401219v] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Terahertz (0.1-30 THz) radiation reveals a wealth of information that is relevant for material, biological, and medical sciences with applications that span chemical sensing, high-speed electronics, and coherent control of semiconductor quantum bits. To date, there have been no methods capable of controlling terahertz (THz) radiation at molecular scales. Here we report both generation and detection of broadband terahertz field from 10 nm scale oxide nanojunctions. Frequency components of ultrafast optical radiation are mixed at these nanojunctions, producing broadband THz emission. These same devices detect THz electric fields with comparable spatial resolution. This unprecedented control, on a scale of 4 orders of magnitude smaller than the diffraction limit, creates a pathway toward THz-bandwidth spectroscopy and control of individual nanoparticles and molecules.
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Affiliation(s)
- Yanjun Ma
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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Jacob R, Winnerl S, Fehrenbacher M, Bhattacharyya J, Schneider H, Wenzel MT, Ribbeck HGV, Eng LM, Atkinson P, Schmidt OG, Helm M. Intersublevel spectroscopy on single InAs-quantum dots by terahertz near-field microscopy. NANO LETTERS 2012; 12:4336-4340. [PMID: 22775149 DOI: 10.1021/nl302078w] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Using scattering-type near-field infrared microscopy in combination with a free-electron laser, intersublevel transitions in buried single InAs quantum dots are investigated. The experiments are performed at room temperature on doped self-assembled quantum dots capped with a 70 nm GaAs layer. Clear near-field contrast of single dots is observed when the photon energy of the incident beam matches intersublevel transition energies, namely the p-d and s-d transition of conduction band electrons confined in the dots. The observed room-temperature line width of 5-8 meV of these resonances in the mid-infrared range is significantly below the inhomogeneously broadened spectral lines of quantum dot ensembles. The experiment highlights the strength of near-field microspectroscopy by demonstrating signals from bound-to-bound transitions of single electrons in a probe volume of the order of (100 nm)(3).
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Affiliation(s)
- Rainer Jacob
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 51 01 19, 01314 Dresden, Germany
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Hwang IC, Kumar R, Kim ND, Chun Y, Lee JW, Kumar P, Mana RS, Choi C, Lee JR, Kim KS. Controlling metal nanotoppings on the tip of silicide nanostructures. NANOTECHNOLOGY 2009; 20:245605. [PMID: 19471081 DOI: 10.1088/0957-4484/20/24/245605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Utilizing the difference in surface tension between SiO2 and metal catalysts (Mn2+, Ni2+), we show how metals form nanoshells, nanodiscs and nanospheres at the tips of the SiO2 nanostructures of nanocones, nanorods and nanowires. For the Mn2+ catalyst (i), SiO2-nanocones are formed with the hemispherical convex cap of the MnO/SiO2 composite. For the Ni2+ catalyst (ii), SiO2 nanowires are grown due to the concave shape of SiO2 surrounding the multi-faceted NiSi particles at their tip. For the Mn2+/Ni2+ catalyst (iii), SiO2 nanorods are formed with large-sized spherical ferromagnetic single Ni nanocrystals (50-200 nm in diameter) surrounded by the concave MnO2/SiO2 composite at the tip of the SiO2 nanorods. This large-sized spherical formation of the single Ni crystal is possible because Ni is able to be chemically reduced by Mn at 950 degrees C, well below the melting point of Ni (1455 degrees C) due to the alloying effect.
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Affiliation(s)
- In Chul Hwang
- Department of Chemistry, Center for Superfunctional Materials, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea
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Liu Z, Yang Q, Zhang H, Wang L, Li D, Yang D. Magnesium catalyzed growth of SiO(2) hierarchical nanostructures by a thermal evaporation process. NANOTECHNOLOGY 2008; 19:165601. [PMID: 21825645 DOI: 10.1088/0957-4484/19/16/165601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
SiO(2) hierarchical nanostructures consisting of a wire-like main stem and lots of rod-like sub-branches have been synthesized by a magnesium catalyzed thermal evaporation process. It is indicated that magnesium plays a critical role in the synthesis of SiO(2) hierarchical nanostructures including promotion for SiO evaporation and hierarchical-like growth of SiO(2). Moreover, the photoluminescence (PL) analysis of the SiO(2) hierarchical nanostructures reveals that blue and ultraviolet (UV) emissions are detected, which are different from those of other SiO(2) nanostructures. Finally, the growth mechanism and PL emission of SiO(2) hierarchical nanostructures have been preliminarily discussed.
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Affiliation(s)
- Zhihong Liu
- State Key Lab of Silicon Materials and Department of Materials and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
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Houel J, Sauvage S, Boucaud P, Dazzi A, Prazeres R, Glotin F, Ortéga JM, Miard A, Lemaître A. Ultraweak-absorption microscopy of a single semiconductor quantum dot in the midinfrared range. PHYSICAL REVIEW LETTERS 2007; 99:217404. [PMID: 18233255 DOI: 10.1103/physrevlett.99.217404] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Indexed: 05/25/2023]
Abstract
We show that we can measure the room temperature ultraweak absorption of a single buried semiconductor quantum dot. This is achieved by monitoring the deformation field induced by the absorption of midinfrared laser pulses and locally detected with an atomic force microscope tip. The absorption is spectrally and spatially resolved around lambda approximately 10 microm wavelength with 60 nm lateral resolution (lambda/150). The electronic S-D intersublevel absorption of a single quantum dot is identified around 120 meV and exhibits a homogeneous linewidth of approximately 10 meV at room temperature.
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Affiliation(s)
- Julien Houel
- Institut d'Electronique Fondamentale CNRS, UMR8622, Université Paris-Sud, F-91405, Orsay, France
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Borri P, Langbein W. Four-wave mixing dynamics of excitons in InGaAs self-assembled quantum dots. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2007; 19:295201. [PMID: 21483053 DOI: 10.1088/0953-8984/19/29/295201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this paper we summarize our experimental work on the dephasing of excitons in self-assembled InAs/GaAs quantum dots, measured using a sensitive four-wave mixing technique in heterodyne detection. Transient four-wave mixing is a powerful technique to measure not only exciton dephasing times but also fine-structure splitting energies and exciton-biexciton binding energies which are important physical parameters for the implementation of quantum dots as source of polarization-entangled photon pairs and in the design of quantum algorithms. The scope of this paper is to review and discuss, in the context of present theories and in comparison with other experiments in the literature, the most significant results of our study on a series of thermally annealed quantum dots exhibiting systematic differences in the excitonic recombination energies and quantum confinement potentials. We will highlight the main outcomes of these measurements and give a perspective in terms of open questions that still need to be investigated, possible new experiments and potential areas of interest.
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Affiliation(s)
- Paola Borri
- School of Biosciences, Cardiff University, Cardiff CF10 3TL, UK
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Patton B, Woggon U, Langbein W. Coherent control and polarization readout of individual excitonic states. PHYSICAL REVIEW LETTERS 2005; 95:266401. [PMID: 16486377 DOI: 10.1103/physrevlett.95.266401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Indexed: 05/06/2023]
Abstract
We present measurements and simulations of coherent control and readout of the polarization in individual exciton states. The readout is accomplished by transient four-wave mixing detected by heterodyne spectral interferometry. We observe Rabi oscillations in the polarization, which show half the period of the Rabi oscillations in the population. A decrease of the oscillation amplitude with pulse area is observed, which is not accompanied by a change in the dephasing time. This suggests the transfer of the excitation to other states as the origin of the Rabi-oscillation damping. Detuning of the excitation enables the control of the polarization in phase and amplitude and is in qualitative agreement with simulations for a two-level system. Additionally, simultaneous Rabi flopping of several spatially and energetically close exciton states is demonstrated.
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Affiliation(s)
- B Patton
- Fachbereich Physik, Universität Dortmund, Germany
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Hohenester U, Goldoni G, Molinari E. Dark-state luminescence of macroatoms at the near field. PHYSICAL REVIEW LETTERS 2005; 95:216802. [PMID: 16384169 DOI: 10.1103/physrevlett.95.216802] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Indexed: 05/05/2023]
Abstract
We theoretically analyze the optical near-field response of a semiconductor macroatom induced by local monolayer fluctuations in the thickness of a semiconductor quantum well, where the large active volume results in a strong enhancement of the light-matter coupling. We find that in the near-field regime bright and dark excitonic states become mixed, opening new channels for the coupling to the electromagnetic field. As a consequence, ultranarrow luminescence lines appear in the simulated two-photon experiments, corresponding to very long lived excitonic states, which undergo Stark shift and Rabi splitting at relatively small field intensities.
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Affiliation(s)
- Ulrich Hohenester
- Institut für Physik, Karl-Franzens-Universität Graz, Universitätsplatz 5, 8010 Graz, Austria.
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11
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Colas des Francs G, Girard C, Juan M, Dereux A. Energy transfer in near-field optics. J Chem Phys 2005; 123:174709. [PMID: 16375559 DOI: 10.1063/1.2101567] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
When the probe tip of a near-field optical microscope illuminates nanoparticles with marked absorption bands, a large number of photons are absorbed before reaching the detector. These energy losses enhance the dark contrast usually observed in the vicinity of metallic nanoparticles. We demonstrate theoretically that this phenomenon can be exploited to image, in the optical frequency range, dissipative domains with a nanometer scale resolution. Simulations performed with noble-metal particles indicate that the detected signal significantly drops down when the excitation frequency is approaching the plasmon resonance of the particles.
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Affiliation(s)
- Gérard Colas des Francs
- Equipe Optique Submicronique, Laboratoire de Physique Université de Bourgogne/Centre National de la Recherche Scientifique, 9 Avenue Alain Savary, F-21078 Dijon, France.
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12
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Langbein W, Patton B. Microscopic measurement of photon echo formation in groups of individual excitonic transitions. PHYSICAL REVIEW LETTERS 2005; 95:017403. [PMID: 16090657 DOI: 10.1103/physrevlett.95.017403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Indexed: 05/03/2023]
Abstract
The third-order polarization emitted from groups of individual localized excitonic transitions after pulsed optical excitation is measured. We observe the evolution of the nonlinear response from the case of a free polarization decay for a single transition, to that of a photon echo for many transitions. The echo is shown to arise from the mutual rephasing of the emission from individual transitions.
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Affiliation(s)
- Wolfgang Langbein
- Department of Physics and Astronomy, Cardiff University, Cardiff CF24 3YB, United Kingdom.
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Vasa P, Singh BP, Ayyub P. Coherence properties of the photoluminescence from CdS-ZnO nanocomposite thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2005; 17:189-197. [PMID: 21690678 DOI: 10.1088/0953-8984/17/1/017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The application of semiconductor quantum dots in important new areas such as random lasing and quantum-information processing requires knowledge of the coherence of the optical emission from such systems. We report the first direct experimental estimation of the coherence in the light emitted by a nanoparticle ensemble. The photoluminescence from a two-phase nanocomposite CdS-ZnO thin film (with a characteristic grain size of 2-3 nm for both the chemical phases) possesses an appreciable degree of spatial and temporal coherence at room temperature. The degree of spatial coherence was estimated from the classical Young's double slit experiment. We also discuss a simple technique for estimating the degree of spectral coherence of the photoluminescence from thin films.
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Affiliation(s)
- Parinda Vasa
- Department of Condensed Matter Physics and Material Science, Tata Institute of Fundamental Research, Mumbai 400005, India
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Imura K, Nagahara T, Okamoto H. Imaging of Surface Plasmon and Ultrafast Dynamics in Gold Nanorods by Near-Field Microscopy. J Phys Chem B 2004. [DOI: 10.1021/jp047950h] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kohei Imura
- Institute for Molecular Science and The Graduate University for Advanced Studies, Okazaki 444-8585, Japan
| | - Tetsuhiko Nagahara
- Institute for Molecular Science and The Graduate University for Advanced Studies, Okazaki 444-8585, Japan
| | - Hiromi Okamoto
- Institute for Molecular Science and The Graduate University for Advanced Studies, Okazaki 444-8585, Japan
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Shen Y, Lin TC, Dai J, Markowicz P, Prasad PN. Near-Field Optical Imaging of Transient Absorption Dynamics in Organic Nanocrystals. J Phys Chem B 2003. [DOI: 10.1021/jp030376+] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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Matsuda K, Saiki T, Nomura S, Mihara M, Aoyagi Y, Nair S, Takagahara T. Near-field optical mapping of exciton wave functions in a GaAs quantum dot. PHYSICAL REVIEW LETTERS 2003; 91:177401. [PMID: 14611375 DOI: 10.1103/physrevlett.91.177401] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2003] [Indexed: 05/24/2023]
Abstract
Near-field photoluminescence imaging spectroscopy of naturally occurring GaAs quantum dots (QDs) is presented. We successfully mapped out center-of -mass wave functions of an exciton confined in a GaAs QD in real space due to the enhancement of spatial resolution up to 30 nm. As a consequence, we discovered that the spatial profile of the exciton emission, which reflects the shape of a monolayer-high island, differs from that of biexciton emission, due to different distributions of the polarization field for the exciton and biexciton recombinations. This novel technique can be extensively applied to wave function engineering in the design and the fabrication of quantum devices.
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Affiliation(s)
- K Matsuda
- Kanagawa Academy of Science and Technology, 3-2-1 Sakado, Takatsu, Kawasaki, Japan.
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Dowling JP, Milburn GJ. Quantum technology: the second quantum revolution. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2003; 361:1655-1674. [PMID: 12952679 DOI: 10.1098/rsta.2003.1227] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We are currently in the midst of a second quantum revolution. The first quantum revolution gave us new rules that govern physical reality. The second quantum revolution will take these rules and use them to develop new technologies. In this review we discuss the principles upon which quantum technology is based and the tools required to develop it. We discuss a number of examples of research programs that could deliver quantum technologies in coming decades including: quantum information technology, quantum electromechanical systems, coherent quantum electronics, quantum optics and coherent matter technology.
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Affiliation(s)
- Jonathan P Dowling
- Quantum Computing Technologies Group, Section 367, Jet Propulsion Laboratory, Pasadena, CA 91109, USA
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Piermarocchi C, Chen P, Sham LJ, Steel DG. Optical RKKY interaction between charged semiconductor quantum dots. PHYSICAL REVIEW LETTERS 2002; 89:167402. [PMID: 12398754 DOI: 10.1103/physrevlett.89.167402] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2002] [Indexed: 05/24/2023]
Abstract
We show how a spin interaction between electrons localized in neighboring quantum dots can be induced and controlled optically. The coupling is generated via virtual excitation of delocalized excitons and provides an efficient coherent control of the spins. This quantum manipulation can be realized in the adiabatic limit and is robust against decoherence by spontaneous emission. Applications to the realization of quantum gates, scalable quantum computers, and to the control of magnetization in an array of charged dots are proposed.
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Affiliation(s)
- C Piermarocchi
- Department of Physics, University of California San Diego, La Jolla 92093-0319, USA
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Zhao H, Moehl S, Kalt H. Coherence length of excitons in a semiconductor quantum well. PHYSICAL REVIEW LETTERS 2002; 89:097401. [PMID: 12190436 DOI: 10.1103/physrevlett.89.097401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2002] [Indexed: 05/23/2023]
Abstract
We report on the first experimental determination of the coherence length of excitons in semiconductors using the combination of spatially resolved photoluminescence with phonon sideband spectroscopy. The coherence length of excitons in ZnSe quantum wells is determined to be 300-400 nm, about 25-30 times the exciton de Broglie wavelength. With increasing exciton kinetic energy, the coherence length decreases slowly. The discrepancy between the coherence lengths measured and calculated by considering only the acoustic-phonon scattering suggests an important influence of static disorder.
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Affiliation(s)
- Hui Zhao
- Institut für Angewandte Physik, Universität Karlsruhe, D-76128 Karlsruhe, Germany
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Balistreri ML, Gersen H, Korterik JP, Kuipers L, van Hulst NF. Tracking femtosecond laser pulses in space and time. Science 2001; 294:1080-2. [PMID: 11691986 DOI: 10.1126/science.1065163] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We show that the propagation of a femtosecond laser pulse inside a photonic structure can be directly visualized and tracked as it propagates using a time-resolved photon scanning tunneling microscope. From the time-dependent and phase-sensitive measurements, both the group velocity and the phase velocity are unambiguously and simultaneously determined. It is expected that this technique will find applications in the investigation of the local dynamic behavior of photonic crystals and integrated optical circuits.
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Affiliation(s)
- M L Balistreri
- Applied Optics group, Department of Applied Physics and MESA(+) Research Institute, University of Twente, Post Office Box 217, 7500 AE Enschede, Netherlands
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Affiliation(s)
- S W Koch
- Department of Physics, Philipps University, 35032 Marburg, Germany.
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