Physikhttp://kops.uni-konstanz.de:80/handle/123456789/102019-04-19T05:27:16Z2019-04-19T05:27:16ZPurcell Effect and Photoluminescence Emission Enhancement of Individual CdSe/CdS/PMMA Nano Particles Coupled to Metallic Bullseye ResonatorsWerschler, Florianpop218056Lindner, Benjaminpop233447Hinz, Christopherpop189540de Roo, Tjaardpop190706Mecking, Stefanpop73199Seletskiy, Denis V.pop238373Leitenstorfer, Alfredpop66822123456789/456812019-04-19T01:14:44Z2017Purcell Effect and Photoluminescence Emission Enhancement of Individual CdSe/CdS/PMMA Nano Particles Coupled to Metallic Bullseye Resonators
Werschler, Florian; Lindner, Benjamin; Hinz, Christopher; de Roo, Tjaard; Mecking, Stefan; Seletskiy, Denis V.; Leitenstorfer, Alfred
Polymer-capped colloidal semiconductor quantum dots [1] offer a robust material system for time-resolved analysis and individual control of ultrafast charge carrier dynamics [2]. This goal necessitates a strong enhancement of light-matter interaction. In this work we demonstrate an efficient coupling of individual CdSe/CdS/PMMA quantum dots (QDs) to plasmonic resonators formed out of multiple concentric rings patterned in a 280-nm thick gold layer. Such a “bullseye” design allows for efficient manipulation of single QDs into the center of the antenna while imposing no polarization selectivity [3]. As a result, we achieve a dramatic increase of the photoluminescence (PL) emission intensity and the radiative decay rates due to the Purcell effect.
2017Werschler, FlorianLindner, BenjaminHinz, Christopherde Roo, TjaardMecking, StefanSeletskiy, Denis V.Leitenstorfer, Alfred530Polymer-capped colloidal semiconductor quantum dots [1] offer a robust material system for time-resolved analysis and individual control of ultrafast charge carrier dynamics [2]. This goal necessitates a strong enhancement of light-matter interaction. In this work we demonstrate an efficient coupling of individual CdSe/CdS/PMMA quantum dots (QDs) to plasmonic resonators formed out of multiple concentric rings patterned in a 280-nm thick gold layer. Such a “bullseye” design allows for efficient manipulation of single QDs into the center of the antenna while imposing no polarization selectivity [3]. As a result, we achieve a dramatic increase of the photoluminescence (PL) emission intensity and the radiative decay rates due to the Purcell effect.IEEEINPROCEEDINGSeng10.1109/CLEOE-EQEC.2017.8087608978-1-5090-6736-72017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO Europe-EQEC) : 25-29 June 20172019-04-18T11:59:43+02:00123456789/412017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO Europe-EQEC) : 25-29 June 2017. - Piscataway, NJ : IEEE, 2017. - EG_5_4. - ISBN 978-1-5090-6736-7München2017-06-25Piscataway, NJ2017 European Conference on Lasers and Electro-Optics and European Quantum Electronics Conference2017-06-292019-04-18T09:59:43ZQuantum sound on a chipBurkard, Guidopop205895123456789/456732019-04-18T01:14:40Z2019-04Quantum sound on a chip
Burkard, Guido
A nanoelectromechanical system made from a nanobeam embedded in a phononic crystal and coupled to a pair of superconducting microwave oscillators can couple hypersonic sound quanta at 0.425 GHz and light quanta with high coherence.
2019-04Burkard, Guido530A nanoelectromechanical system made from a nanobeam embedded in a phononic crystal and coupled to a pair of superconducting microwave oscillators can couple hypersonic sound quanta at 0.425 GHz and light quanta with high coherence.JOURNAL_ARTICLEeng10.1038/s41565-019-0391-41748-33871748-3395311312144Nature Nanotechnology2019-04-17T14:12:01+02:00123456789/41Nature Nanotechnology ; 14 (2019), 4. - S. 311-312. - ISSN 1748-3387. - eISSN 1748-3395true2019-04-17T12:12:01ZColloidal Brazil nut effect in microswimmer mixtures induced by motility contrastJahanshahi, SoudehLozano, Celiapop516065ten Hagen, BorgeBechinger, Clemenspop512842Löwen, Hartmut123456789/456192019-04-11T01:14:30Z2019-03-21Colloidal Brazil nut effect in microswimmer mixtures induced by motility contrast
Jahanshahi, Soudeh; Lozano, Celia; ten Hagen, Borge; Bechinger, Clemens; Löwen, Hartmut
We numerically and experimentally study the segregation dynamics in a binary mixture of microswimmers which move on a two-dimensional substrate in a static periodic triangular-like light intensity field. The motility of the active particles is proportional to the imposed light intensity, and they possess a motility contrast, i.e., the prefactor depends on the species. In addition, the active particles also experience a torque aligning their motion towards the direction of the negative intensity gradient. We find a segregation of active particles near the intensity minima where typically one species is localized close to the minimum and the other one is centered around in an outer shell. For a very strong aligning torque, there is an exact mapping onto an equilibrium system in an effective external potential that is minimal at the intensity minima. This external potential is similar to (height-dependent) gravity such that one can define effective “heaviness” of the self-propelled particles. In analogy to shaken granular matter in gravity, we define a “colloidal Brazil nut effect” if the heavier particles are floating on top of the lighter ones. Using extensive Brownian dynamics simulations, we identify system parameters for the active colloidal Brazil nut effect to occur and explain it based on a generalized Archimedes’ principle within the effective equilibrium model: heavy particles are levitated in a dense fluid of lighter particles if their effective mass density is lower than that of the surrounding fluid. We also perform real-space experiments on light-activated self-propelled colloidal mixtures which confirm the theoretical predictions.
2019-03-21Jahanshahi, SoudehLozano, Celiaten Hagen, BorgeBechinger, ClemensLöwen, Hartmut530We numerically and experimentally study the segregation dynamics in a binary mixture of microswimmers which move on a two-dimensional substrate in a static periodic triangular-like light intensity field. The motility of the active particles is proportional to the imposed light intensity, and they possess a motility contrast, i.e., the prefactor depends on the species. In addition, the active particles also experience a torque aligning their motion towards the direction of the negative intensity gradient. We find a segregation of active particles near the intensity minima where typically one species is localized close to the minimum and the other one is centered around in an outer shell. For a very strong aligning torque, there is an exact mapping onto an equilibrium system in an effective external potential that is minimal at the intensity minima. This external potential is similar to (height-dependent) gravity such that one can define effective “heaviness” of the self-propelled particles. In analogy to shaken granular matter in gravity, we define a “colloidal Brazil nut effect” if the heavier particles are floating on top of the lighter ones. Using extensive Brownian dynamics simulations, we identify system parameters for the active colloidal Brazil nut effect to occur and explain it based on a generalized Archimedes’ principle within the effective equilibrium model: heavy particles are levitated in a dense fluid of lighter particles if their effective mass density is lower than that of the surrounding fluid. We also perform real-space experiments on light-activated self-propelled colloidal mixtures which confirm the theoretical predictions.JOURNAL_ARTICLEeng10.1063/1.50830980021-96061089-769015011The Journal of Chemical Physics2019-04-10T14:20:19+02:00123456789/41The Journal of Chemical Physics ; 150 (2019), 11. - 114902. - ISSN 0021-9606. - eISSN 1089-7690true2019-04-10T12:20:19ZtrueAntiferromagnetic Magnons as Highly Squeezed Fock States underlying Quantum CorrelationsKamra, Akashdeeppop503200Thingstad, EvenRastelli, Gianlucapop242135Duine, Rembert A.Brataas, ArneBelzig, Wolfgangpop137343Sudbø, Asle123456789/456122019-04-11T01:14:44Z2019-04-09T09:18:01ZAntiferromagnetic Magnons as Highly Squeezed Fock States underlying Quantum Correlations
Kamra, Akashdeep; Thingstad, Even; Rastelli, Gianluca; Duine, Rembert A.; Brataas, Arne; Belzig, Wolfgang; Sudbø, Asle
Employing the concept of two-mode squeezed states from quantum optics, we demonstrate a revealing physical picture for the antiferromagnetic ground state and excitations. Superimposed on a N\'eel ordered configuration, a spin-flip restricted to one of the sublattices is called a sublattice-magnon. We show that an antiferromagnetic spin-up magnon is comprised by a quantum superposition of states with $n+1$ spin-up and $n$ spin-down sublattice-magnons, and is thus an enormous excitation despite its unit net spin. Consequently, its large sublattice-spin can amplify its coupling to other excitations. Employing von Neumann entropy as a measure, we show that the antiferromagnetic eigenmodes manifest a high degree of entanglement between the two sublattices, thereby establishing antiferromagnets as reservoirs for strong quantum correlations. Based on these novel insights, we outline strategies for exploiting the strong quantum character of antiferromagetic (squeezed-)magnons.
2019-04-09T09:18:01ZKamra, AkashdeepThingstad, EvenRastelli, GianlucaDuine, Rembert A.Brataas, ArneBelzig, WolfgangSudbø, Asle530Employing the concept of two-mode squeezed states from quantum optics, we demonstrate a revealing physical picture for the antiferromagnetic ground state and excitations. Superimposed on a N\'eel ordered configuration, a spin-flip restricted to one of the sublattices is called a sublattice-magnon. We show that an antiferromagnetic spin-up magnon is comprised by a quantum superposition of states with $n+1$ spin-up and $n$ spin-down sublattice-magnons, and is thus an enormous excitation despite its unit net spin. Consequently, its large sublattice-spin can amplify its coupling to other excitations. Employing von Neumann entropy as a measure, we show that the antiferromagnetic eigenmodes manifest a high degree of entanglement between the two sublattices, thereby establishing antiferromagnets as reservoirs for strong quantum correlations. Based on these novel insights, we outline strategies for exploiting the strong quantum character of antiferromagetic (squeezed-)magnons.WORKINGPAPERurn:nbn:de:bsz:352-2-yeoku8f15ncn2eng2019-04-10T11:06:51+02:00123456789/412019-04-10T09:06:51Ztrue