@article{HeilSchreiberGoetzetal.2018, author = {Heil, Hannah S. and Schreiber, Benjamin and G{\"o}tz, Ralph and Emmerling, Monika and Dabauvalle, Marie-Christine and Krohne, Georg and H{\"o}fling, Sven and Kamp, Martin and Sauer, Markus and Heinze, Katrin G.}, title = {Sharpening emitter localization in front of a tuned mirror}, series = {Light: Science \& Applications}, volume = {7}, journal = {Light: Science \& Applications}, doi = {10.1038/s41377-018-0104-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228080}, year = {2018}, abstract = {Single-molecule localization microscopy (SMLM) aims for maximized precision and a high signal-to-noise ratio1. Both features can be provided by placing the emitter in front of a metal-dielectric nanocoating that acts as a tuned mirror2,3,4. Here, we demonstrate that a higher photon yield at a lower background on biocompatible metal-dielectric nanocoatings substantially improves SMLM performance and increases the localization precision by up to a factor of two. The resolution improvement relies solely on easy-to-fabricate nanocoatings on standard glass coverslips and is spectrally and spatially tunable by the layer design and wavelength, as experimentally demonstrated for dual-color SMLM in cells.}, language = {en} } @article{KreinbergPorteSchickeetal.2019, author = {Kreinberg, S{\"o}ren and Porte, Xavier and Schicke, David and Lingnau, Benjamin and Schneider, Christian and H{\"o}fling, Sven and Kanter, Ido and L{\"u}dge, Kathy and Reitzenstein, Stephan}, title = {Mutual coupling and synchronization of optically coupled quantum-dot micropillar lasers at ultra-low light levels}, series = {Nature Communications}, volume = {10}, journal = {Nature Communications}, doi = {10.1038/s41467-019-09559-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229811}, year = {2019}, abstract = {Synchronization of coupled oscillators at the transition between classical physics and quantum physics has become an emerging research topic at the crossroads of nonlinear dynamics and nanophotonics. We study this unexplored field by using quantum dot microlasers as optical oscillators. Operating in the regime of cavity quantum electrodynamics (cQED) with an intracavity photon number on the order of 10 and output powers in the 100 nW range, these devices have high β-factors associated with enhanced spontaneous emission noise. We identify synchronization of mutually coupled microlasers via frequency locking associated with a sub-gigahertz locking range. A theoretical analysis of the coupling behavior reveals striking differences from optical synchronization in the classical domain with negligible spontaneous emission noise. Beyond that, additional self-feedback leads to zero-lag synchronization of coupled microlasers at ultra-low light levels. Our work has high potential to pave the way for future experiments in the quantum regime of synchronization.}, language = {en} } @article{SchneiderGlazovKornetal.2018, author = {Schneider, Christian and Glazov, Mikhail M. and Korn, Tobias and H{\"o}fling, Sven and Urbaszek, Bernhard}, title = {Two-dimensional semiconductors in the regime of strong light-matter coupling}, series = {Nature Communications}, volume = {9}, journal = {Nature Communications}, doi = {10.1038/s41467-018-04866-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-231295}, year = {2018}, abstract = {The optical properties of transition metal dichalcogenide monolayers are widely dominated by excitons, Coulomb-bound electron-hole pairs. These quasi-particles exhibit giant oscillator strength and give rise to narrow-band, well-pronounced optical transitions, which can be brought into resonance with electromagnetic fields in microcavities and plasmonic nanostructures. Due to the atomic thinness and robustness of the monolayers, their integration in van der Waals heterostructures provides unique opportunities for engineering strong light-matter coupling. We review first results in this emerging field and outline future opportunities and challenges.}, language = {en} } @article{KreinbergGrbešićStraussetal.2018, author = {Kreinberg, S{\"o}ren and Grbešić, Tomislav and Strauß, Max and Carmele, Alexander and Emmerling, Monika and Schneider, Christian and H{\"o}fling, Sven and Porte, Xavier and Reitzenstein, Stephan}, title = {Quantum-optical spectroscopy of a two-level system using an electrically driven micropillar laser as a resonant excitation source}, series = {Light: Science \& Applications}, volume = {7}, journal = {Light: Science \& Applications}, doi = {10.1038/s41377-018-0045-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229802}, year = {2018}, abstract = {Two-level emitters are the main building blocks of photonic quantum technologies and are model systems for the exploration of quantum optics in the solid state. Most interesting is the strict resonant excitation of such emitters to control their occupation coherently and to generate close to ideal quantum light, which is of utmost importance for applications in photonic quantum technology. To date, the approaches and experiments in this field have been performed exclusively using bulky lasers, which hinders the application of resonantly driven two-level emitters in compact photonic quantum systems. Here we address this issue and present a concept for a compact resonantly driven single-photon source by performing quantum-optical spectroscopy of a two-level system using a compact high-β microlaser as the excitation source. The two-level system is based on a semiconductor quantum dot (QD), which is excited resonantly by a fiber-coupled electrically driven micropillar laser. We dress the excitonic state of the QD under continuous wave excitation, and trigger the emission of single photons with strong multi-photon suppression (g\(^{(2)}\)(0)=0.02) and high photon indistinguishability (V = 57±9\%) via pulsed resonant excitation at 156 MHz. These results clearly demonstrate the high potential of our resonant excitation scheme, which can pave the way for compact electrically driven quantum light sources with excellent quantum properties to enable the implementation of advanced quantum communication protocols.}, language = {en} } @article{WaldherrLundtKlaasetal.2018, author = {Waldherr, Max and Lundt, Nils and Klaas, Martin and Betzold, Simon and Wurdack, Matthias and Baumann, Vasilij and Estrecho, Eliezer and Nalitov, Anton and Cherotchenko, Evgenia and Cai, Hui and Ostrovskaya, Elena A. and Kavokin, Alexey V. and Tongay, Sefaattin and Klembt, Sebastian and H{\"o}fling, Sven and Schneider, Christian}, title = {Observation of bosonic condensation in a hybrid monolayer MoSe2-GaAs microcavity}, series = {Nature Communications}, volume = {9}, journal = {Nature Communications}, doi = {10.1038/s41467-018-05532-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-233280}, year = {2018}, abstract = {Bosonic condensation belongs to the most intriguing phenomena in physics, and was mostly reserved for experiments with ultra-cold quantum gases. More recently, it became accessible in exciton-based solid-state systems at elevated temperatures. Here, we demonstrate bosonic condensation driven by excitons hosted in an atomically thin layer of MoSe2, strongly coupled to light in a solid-state resonator. The structure is operated in the regime of collective strong coupling between a Tamm-plasmon resonance, GaAs quantum well excitons, and two-dimensional excitons confined in the monolayer crystal. Polariton condensation in a monolayer crystal manifests by a superlinear increase of emission intensity from the hybrid polariton mode, its density-dependent blueshift, and a dramatic collapse of the emission linewidth, a hallmark of temporal coherence. Importantly, we observe a significant spin-polarization in the injected polariton condensate, a fingerprint for spin-valley locking in monolayer excitons. Our results pave the way towards highly nonlinear, coherent valleytronic devices and light sources.}, language = {en} }