TY  - JOUR
A1  - Yu, Leo
A1  - Natarajan, Chandra M.
A1  - Horikiri, Tomoyuki
A1  - Langrock, Carsten
A1  - Pelc, Jason S.
A1  - Tanner, Michael G.
A1  - Abe, Eisuke
A1  - Maier, Sebastian
A1  - Schneider, Christian
A1  - Höfling, Sven
A1  - Kamp, Martin
A1  - Hadfield, Robert H.
A1  - Fejer, Martin M.
A1  - Yamamoto, Yoshihisa
T1  - Two-photon interference at telecom wavelengths for time-bin-encoded single photons from quantum-dot spin qubits
JF  - Nature Communications
N2  - Practical quantum communication between remote quantum memories rely on single photons at telecom wavelengths. Although spin-photon entanglement has been demonstrated in atomic and solid-state qubit systems, the produced single photons at short wavelengths and with polarization encoding are not suitable for long-distance communication, because they suffer from high propagation loss and depolarization in optical fibres. Establishing entanglement between remote quantum nodes would further require the photons generated from separate nodes to be indistinguishable. Here, we report the observation of correlations between a quantum-dot spin and a telecom single photon across a 2-km fibre channel based on time-bin encoding and background-free frequency downconversion. The downconverted photon at telecom wavelengths exhibits two-photon interference with another photon from an independent source, achieving a mean wavepacket overlap of greater than 0.89 despite their original wavelength mismatch (900 and 911 nm). The quantum-networking operations that we demonstrate will enable practical communication between solid-state spin qubits across long distances.
KW  - atom
KW  - 1550 nm
KW  - up-conversion
KW  - heralded entanglement
KW  - emission
KW  - interface
KW  - generation
KW  - communication
KW  - downconversion
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-138677
VL  - 6
ER  - 
TY  - JOUR
A1  - Lee, Chang-Min
A1  - Lim, Hee-Jin
A1  - Schneider, Christian
A1  - Maier, Sebastian
A1  - Höfling, Sven
A1  - Kamp, Martin
A1  - Lee, Yong-Hee
T1  - Efficient single photon source based on \(\mu\)-fibre-coupled tunable microcavity
JF  - Scientific Reports
N2  - Efficient and fast on-demand single photon sources have been sought after as critical components of quantum information science. We report an efficient and tunable single photon source based on an InAs quantum dot (QD) embedded in a photonic crystal cavity coupled with a highly curved \(\mu\)-fibre. Exploiting evanescent coupling between the \(\mu\)-fibre and the cavity, a high collection efficiency of 23% and Purcell-enhanced spontaneous emissions are observed. In our scheme, the spectral position of a resonance can be tuned by as much as 1.5 nm by adjusting the contact position of the \(\mu\)-fibre, which increases the spectral coupling probability between the QD and the cavity mode. Taking advantage of the high photon count rate and the tunability, the collection efficiencies and the decay rates are systematically investigated as a function of the QD-cavity detuning.
KW  - tapers
KW  - semiconductor quantum dots
KW  - crystal
KW  - nanowire
KW  - generation
KW  - nanoactivity
KW  - mode
KW  - emission
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-145835
VL  - 5
IS  - 14309
ER  - 
TY  - JOUR
A1  - Görl, Daniel
A1  - Zhang, Xin
A1  - Stepanenko, Vladimir
A1  - Würthner, Frank
T1  - Supramolecular block copolymers by kinetically controlled co-self-assembly of planar and core-twisted perylene bisimides
JF  - Nature Communications
N2  - New synthetic methodologies for the formation of block copolymers have revolutionized polymer science within the last two decades. However, the formation of supramolecular block copolymers composed of alternating sequences of larger block segments has not been realized yet. Here we show by transmission electron microscopy (TEM), 2D NMR and optical spectroscopy that two different perylene bisimide dyes bearing either a flat (A) or a twisted (B) core self-assemble in water into supramolecular block copolymers with an alternating sequence of (A\(_{m}\)BB)\(_{n}\). The highly defined ultralong nanowire structure of these supramolecular copolymers is entirely different from those formed upon self-assembly of the individual counterparts, that is, stiff nanorods (A) and irregular nanoworms (B), respectively. Our studies further reveal that the as-formed supramolecular block copolymer constitutes a kinetic self-assembly product that transforms into thermodynamically more stable self-sorted homopolymers upon heating.
KW  - cylindrical micelles
KW  - water
KW  - amplification
KW  - association
KW  - emission
KW  - organization
KW  - polymerization
KW  - dyes
KW  - fluorescent
KW  - aqueous medium
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148657
VL  - 6
IS  - 7009
ER  -