@article{SchlottmannSchickeKruegeretal.2019, author = {Schlottmann, Elisabeth and Schicke, David and Kr{\"u}ger, Felix and Lingnau, Benjamin and Schneider, Christian and H{\"o}fling, Sven and L{\"u}dge, Kathy and Porte, Xavier and Reitzenstein, Stephan}, title = {Stochastic polarization switching induced by optical injection in bimodal quantum-dot micropillar lasers}, series = {Optics Express}, volume = {27}, journal = {Optics Express}, number = {20}, doi = {10.1364/OE.27.028816}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228603}, pages = {28816-28831}, year = {2019}, abstract = {Mutual coupling and injection locking of semiconductor lasers is of great interest in non-linear dynamics and its applications for instance in secure data communication and photonic reservoir computing. Despite its importance, it has hardly been studied in microlasers operating at mu W light levels. In this context, vertically emitting quantum dot micropillar lasers are of high interest. Usually, their light emission is bimodal, and the gain competition of the associated linearly polarized fundamental emission modes results in complex switching dynamics. We report on selective optical injection into either one of the two fundamental mode components of a bimodal micropillar laser. Both modes can lock to the master laser and influence the non-injected mode by reducing the available gain. We demonstrate that the switching dynamics can be tailored externally via optical injection in very good agreement with our theory based on semi-classical rate equations. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, language = {en} } @article{RedlichLingnauHolzingeretal.2016, author = {Redlich, Christoph and Lingnau, Benjamin and Holzinger, Steffen and Schlottmann, Elisabeth and Kreinberg, S{\"o}ren and Schneider, Christian and Kamp, Martin and H{\"o}fling, Sven and Wolters, Janik and Reitzenstein, Stephan and L{\"u}dge, Kathy}, title = {Mode-switching induced super-thermal bunching in quantum-dot microlasers}, series = {New Journal of Physics}, volume = {18}, journal = {New Journal of Physics}, number = {063011}, doi = {10.1088/1367-2630/18/6/063011}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166286}, year = {2016}, abstract = {The super-thermal photon bunching in quantum-dot (QD) micropillar lasers is investigated both experimentally and theoretically via simulations driven by dynamic considerations. Using stochastic multi-mode rate equations we obtain very good agreement between experiment and theory in terms of intensity profiles and intensity-correlation properties of the examined QD micro-laser's emission. Further investigations of the time-dependent emission show that super-thermal photon bunching occurs due to irregular mode-switching events in the bimodal lasers. Our bifurcation analysis reveals that these switchings find their origin in an underlying bistability, such that spontaneous emission noise is able to effectively perturb the two competing modes in a small parameter region. We thus ascribe the observed high photon correlation to dynamical multistabilities rather than quantum mechanical correlations.}, language = {en} } @article{RauHeindelUnsleberetal.2014, author = {Rau, Markus and Heindel, Tobias and Unsleber, Sebastian and Braun, Tristan and Fischer, Julian and Frick, Stefan and Nauerth, Sebastian and Schneider, Christian and Vest, Gwenaelle and Reitzenstein, Stephan and Kamp, Martin and Forchel, Alfred and H{\"o}fling, Sven and Weinfurter, Harald}, title = {Free space quantum key distribution over 500 meters using electrically driven quantum dot single-photon sources-a proof of principle experiment}, series = {New Journal of Physics}, volume = {16}, journal = {New Journal of Physics}, number = {043003}, doi = {10.1088/1367-2630/16/4/043003}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116760}, year = {2014}, abstract = {Highly efficient single-photon sources (SPS) can increase the secure key rate of quantum key distribution (QKD) systems compared to conventional attenuated laser systems. Here we report on a free space QKD test using an electrically driven quantum dot single-photon source (QD SPS) that does not require a separate laser setup for optical pumping and thus allows for a simple and compact SPS QKD system. We describe its implementation in our 500 m free space QKD system in downtown Munich. Emulating a BB84 protocol operating at a repetition rate of 125 MHz, we could achieve sifted key rates of 5-17 kHz with error ratios of 6-9\% and g((2))(0)-values of 0.39-0.76.}, language = {en} } @phdthesis{Reitzenstein2004, author = {Reitzenstein, Stephan}, title = {Monolithische Halbleiternanostrukturen als ballistische Verst{\"a}rker und logische Gatter}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-12177}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2004}, abstract = {Im Rahmen dieser Arbeit wurden monolithische Halbleiternanostrukturen hinsichtlich neuartiger nanoelektronischer Transporteffekte untersucht. Hierbei wurden gezielt der ballistische Charakter des Ladungstransportes in mesoskopischen Strukturen sowie die kapazitive Kopplung einzelner Strukturbereiche ausgenutzt, um ballistische Verst{\"a}rkerelemente und logische Gatter zu realisieren. Die untersuchten Nanostrukturen basieren auf dem zweidimensionalen Elektronengas modulationsdotierter GaAs/AlGaAs-Heterostrukturen und wurden {\"u}ber Elektronenstrahl-Lithographie sowie nasschemische {\"A}tztechniken realisiert. Somit entstanden niederdimensionale Leiter mit Kanalbreiten von wenigen 10 nm, deren Leitwert {\"u}ber planare seitliche Gates elektrisch kontrolliert werden kann. Bei den Transportuntersuchungen, die zum Teil im stark nichtlinearen Transportbereich und bei Temperaturen bis hin zu 300 K durchgef{\"u}hrt wurden, stellte sich das Konzept verzweigter Kanalstrukturen als vielversprechend hinsichtlich der Anwendung f{\"u}r eine neuartige Nanoelektronik heraus. So kann eine im Folgenden als Y-Transistor bezeichnete, verzweigte Kanalstruktur in Abh{\"a}ngigkeit der {\"a}ußeren Beschaltung als Differenzverst{\"a}rker, invertierender Verst{\"a}rker, bistabiles Schaltelement oder aber auch als logisches Gatter eingesetzt werden. Zudem er{\"o}ffnet der Y-Transistor einen experimentellen Zugang zu den nichtklassischen Eigenschaften nanometrischer Kapazit{\"a}ten, die sich von denen rein geometrisch definierter Kapazit{\"a}ten aufgrund der endlichen Zustandsdichte erheblich unterscheiden k{\"o}nnen. F{\"u}r ballistische Y-Verzweigungen tritt zudem ein neuartiger Gleichrichtungseffekt auf, der in Kombination mit den verst{\"a}rkenden Eigenschaften von Y-Transistoren dazu genutzt wurde, kompakte logische Gatter sowie einen ballistischen Halb-Addierer zu realisieren.}, subject = {Transistor}, language = {de} }