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Author: Schmidt, Oliver G. × End date: 2019 × Start date: 2013 × DDC: 530 × DDC: 620 × Has files: Yes ×

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Now showing 1 - 3 of 3
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    Electrically-Pumped Wavelength-Tunable GaAs Quantum Dots Interfaced with Rubidium Atoms
    (Washington, DC : ACS, 2017) Huang, Huiying; Trotta, Rinaldo; Huo, Yongheng; Lettner, Thomas; Wildmann, Johannes S.; Martín-Sánchez, Javier; Huber, Daniel; Reindl, Marcus; Zhang, Jiaxiang; Zallo, Eugenio; Schmidt, Oliver G.; Rastelli, Armando
    We demonstrate the first wavelength-tunable electrically pumped source of nonclassical light that can emit photons with wavelength in resonance with the D2 transitions of 87Rb atoms. The device is fabricated by integrating a novel GaAs single-quantum-dot light-emitting diode (LED) onto a piezoelectric actuator. By feeding the emitted photons into a 75 mm long cell containing warm 87Rb vapor, we observe slow-light with a temporal delay of up to 3.4 ns. In view of the possibility of using 87Rb atomic vapors as quantum memories, this work makes an important step toward the realization of hybrid-quantum systems for future quantum networks.
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    Tuning the magneto-optical response of TbPc2 single molecule magnets by the choice of the substrate
    (London [u.a.] : RSC, 2015) Robaschik, Peter; Fronk, Michael; Toader, Marius; Klyatskaya, Svetlana; Ganss, Fabian; Siles, Pablo F.; Schmidt, Oliver G.; Albrecht, Manfred; Hietschold, Michael; Ruben, Mario; Zahn, Dietrich R.T.; Salvan, Georgeta
    In this work, we investigated the magneto-optical response of thin films of TbPc2 on substrates which are relevant for (spin) organic field effect transistors (SiO2) or vertical spin valves (Co) in order to explore the possibility of implementing TbPc2 in magneto-electronic devices, the functionality of which includes optical reading. The optical and magneto-optical properties of TbPc2 thin films prepared by organic molecular beam deposition (OMBD) on silicon substrates covered with native oxide were investigated by variable angle spectroscopic ellipsometry (VASE) and magneto-optical Kerr effect (MOKE) spectroscopy at room temperature. The magneto-optical activity of the TbPc2 films can be significantly enhanced by one to two orders of magnitude upon changing the molecular orientation (from nearly standing molecules on SiO2/Si substrates to nearly lying molecules on perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) templated SiO2/Si substrates) or by using metallic ferromagnetic substrates (Co).
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    Real-Time IR Tracking of Single Reflective Micromotors through Scattering Tissues
    (Weinheim : Wiley-VCH, 2019) Aziz, Azaam; Medina-Sánchez, Mariana; Koukourakis, Nektarios; Wang, Jiawei; Kuschmierz, Robert; Radner, Hannes; Czarske, Jürgen W.; Schmidt, Oliver G.
    Medical micromotors have the potential to lead to a paradigm shift in future biomedicine, as they may perform active drug delivery, microsurgery, tissue engineering, or assisted fertilization in a minimally invasive manner. However, the translation to clinical treatment is challenging, as many applications of single or few micromotors require real-time tracking and control at high spatiotemporal resolution in deep tissue. Although optical techniques are a popular choice for this task, absorption and strong light scattering lead to a pronounced decrease of the signal-to-noise ratio with increasing penetration depth. Here, a highly reflective micromotor is introduced which reflects more than tenfold the light intensity of simple gold particles and can be precisely navigated by external magnetic fields. A customized optical IR imaging setup and an image correlation technique are implemented to track single micromotors in real-time and label-free underneath phantom and ex vivo mouse skull tissues. As a potential application, the micromotors speed is recorded when moving through different viscous fluids to determine the viscosity of diverse physiological fluids toward remote cardiovascular disease diagnosis. Moreover, the micromotors are loaded with a model drug to demonstrate their cargo-transport capability. The proposed reflective micromotor is suitable as theranostic tool for sub-skin or organ-on-a-chip applications. © 2019 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.