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Physikalisches Kolloquium


13.5.2019 17:15, Raum: T-1004
Prof. Dr. Erich Runge (TU Ilmenau)
Strongly localized, long-lived electromagnetic modes in disordered nanostructures
27.5.2019 17:15, Raum: T-1004
Prof. Dr. Armando Rastelli (Johannes Kepler Universität Linz)
Highly Entangled Photon Pairs from Semiconductor Quantum Dots

Semiconductor quantum dots (QDs) obtained by epitaxial growth are regarded as one of the most promising solid-state sources of triggered single and entangled photons for applications in emerging quantum communication and photonic quantum-information-processing. In this talk, I will introduce the “features and bugs” of QDs in view of their potential applications, followed by a presentation of some of our recent results. In particular, I will focus on GaAs QDs in AlGaAs matrix [1,2], which show a unique combination of appealing features: fast radiative rates, capability of generating near perfectly entangled photon pairs [3] with good indistinguishability [4] and ultralow multiphoton emission probability [5], as well as compatibility with high-throughput photonic structures [6]. These properties were recently used to implement photonic quantum teleportation using photons sequentially emitted by the same quantum dot [7]. I will also show that some of the QD “bugs” can be fixed by integrating them onto piezoelectric actuators [8-12]. Strain provided by such actuators is a powerful tool to bring the emission energy of separate dots into resonance [11], restore broken symmetries [3,10], and also change the polarization properties of the emitted photons [2,12]. I will conclude by discussing the open challenges. References [1] A. Rastelli et al., Phys. Rev. Lett. 92, 166104 (2004). [2] Y. Huo et al., Nature Phys. 10, 46 (2014). [3] D. Huber et al., Phys. Rev. Lett. 121, 033902 (2018). [4] M. Reindl et al., https://arxiv.org/abs/1901.11251 [5] L. Schweickert et al., Appl. Phys. Lett. 112, 093106 (2018). [6] J. Liu et al, https://arxiv.org/abs/1903.01339 (in press in Nature Nanotech.) [7] M. Reindl et al., Science Adv. 4, 12, eaau1255 (2018). [8] A. Rastelli et al, Phys. Status Solidi (b), 249, 687 (2012). [9] J. Martín-Sánchez et al, Adv. Opt. Mater. 4, 682 (2016). [10] R. Trotta et al., Nat. Comm. 7, 10375 (2016). [11] M. Reindl et al., Nano Lett. 17, 4090 (2017). [12] X. Yuan et al., Nat. Comm. 9, 3058 (2018).

17.6.2019 17:15, Raum: T-1004
Prof. Dr. Claus Ropers (Georg-August-Universität Göttingen)
Ultrafast Imaging and Diffraction
1.7.2019 17:15, Raum: T-1004
Prof. Dr. Alexander Urban (LMU München)
A Revolution in Optoelectronics? - The Fascinating Properties of Halide Perovskites
15.7.2019 17:15, Raum: T-1004
Frau Dr. Annina Luck (Fa. Volume Graphics aus Heidelberg)
Alles außer Patienten. Wo und wie (Industrie-)CTs Licht ins Dunkel bringen.

Die Vorträge finden im Hörsaalzentrum Physik (Gebäude T) statt.

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