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  • 2022

  • Bitzer, Andreas (2022): Rettungs-Assistenzsystem für die alpine Rettung (Einblicke in die Forschung). Online verfügbar unter https://www.fhgr.ch/fileadmin/publikationen/forschungsbericht/fhgr-Einblicke_in_die_Forschung_2022.pdf, zuletzt geprüft am 19.05.2022

     

    Abstract: Das Projekt zielt darauf ab, innovative Ansätze aus der Robotik, Sensorik, Regelungstechnik, Datenübertragung und Bilderkennung zu evaluieren, um die alpine Luftrettung technologisch voranzutreiben. Zu diesem Zweck soll ein Prototyp für ein Longline-Rettungs-Assistenzsystem entwickelt werden.

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  • 2019

  • Bitzer, Andreas (2019) : Effiziente Entwicklung von Prototypen . Blog (Studentenfutter) . Online verfügbar unter https://www.suedostschweiz.ch/blogs/studentenfutter/2019-06-28/effiziente-entwicklung-von-prototypen , zuletzt geprüft am 19.02.2021

     

    Abstract: Prototypen versetzen einen Betrachtenden für einen kurzen Moment in die Zukunft und liefern so wichtige Beiträge bei der Entwicklung neuer Produkte. Auch fürs Management dienen sie als anschauliche und verständliche Entscheidungsgrundlage.

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  • Bitzer, Andreas (2019) : Ef­fi­zi­en­te Ent­wick­lung von Pro­to­ty­pen . Blog (FHGR Blog) . Online verfügbar unter https://blog.fhgr.ch/blog/effiziente-entwicklung-von-prototypen/ , zuletzt geprüft am 22.02.2021

     

    Abstract: Prototypen demonstrieren auf anschauliche Weise neuartige Funktionen und ermöglichen die Erprobung innovativer Ansätze.

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  • Reiss, Simon; Lottner, Thomas; Özen, Ali; Bock, Michael; Bitzer, Andreas (2019): On the RF Excitation of Overlapping Stents: Electro-optical E-field Measurements. Digital Poster. Montréal

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  • 2012

  • Merbold, Hannes; Bitzer, Andreas; Carbone, Fabrizio; Murk, Axel; Wallauer, Jan; Walther, Markus; Feurer, Thomas (2012) : Adjusting the functionality of terahertz split-ring resonators through geometry In: Betz, Markus; Elezzabi, Abdulhakem Y.; Song, Jin-Joo; Tsen, Kong-Thon (Hg.): Ultrafast Phenomena and Nanophotonics XVI: SPIE OPTO: San Francisco, California, USA, 21.-26. Januar: SPIE. Digital Library (SPIE Proceedings)

    DOI: https://doi.org/10.1117/12.908107 

    Abstract: We examine planar double split-ring resonators (SRRs) consisting of two concentric rings with either opposite, similar, or asymmetric gap orientation. Depending on the geometry we observe resonance hybridization, metamaterial induced transparency, or the excitation of dark resonances. These properties can be used for SRR based sensing applications, to realize strongly dispersive behavior, or for determining the optical properties of metals. We further find that THz SRRs featuring very narrow gaps on the micro- or nanoscale can provide in-gap enhancement factors of several 10,000, a property particularly useful for the realization of nonlinear THz experiments.

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  • 2011

  • Bitzer, Andreas; Ortner, Alex; Merbold, Hannes; Feurer, Thomas; Walther, Markus (2011): Terahertz near-field microscopy of complementary planar metamaterials: Babinet's principle. In: Optics express 19 (3), S. 2537-2545. Online verfügbar unter https://doi.org/10.1364/OE.19.002537, zuletzt geprüft am 18.06.2021

     

    Abstract: Using terahertz near-field imaging we experimentally investigate the resonant electromagnetic field distributions behind a split-ring resonator and its complementary structure with sub-wavelength spatial resolution. For the out-of-plane components we experimentally verify complementarity of electric and magnetic fields as predicted by Babinet's principle. This duality of near-fields can be used to indirectly map resonant magnetic fields close to metallic microstructures by measuring the electric fields close to their complementary analogues which is particularly useful since magnetic near-fields are still extremely difficult to access in the THz regime. We find excellent agreement between the results from theory, simulation and two different experimental near-field techniques.

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  • Merbold, Hannes; Bitzer, Andreas; Enderli, Florian; Feurer, Thomas (2011): Spatiotemporal Visualization of THz Near-Fields in Metamaterial Arrays. In: Journal of Infrared, Millimeter, and Terahertz Waves 32 (5), S. 570-579. Online verfügbar unter https://doi.org/10.1007/s10762-010-9648-6, zuletzt geprüft am 18.06.2021

     

    Abstract: We present an experimental approach to record the spatiotemporal electric field distribution of coherent broadband THz pulses propagating through planar metamaterial arrays. The electric field can be measured with sub-wavelength precision within a volume that is several wavelengths in size, thus, having the potential to map the near-field to far-field transition of the resonant structures constituting the metamaterial. To demonstrate the potential we present measurements of THz pulses propagating through a planar array of double split-ring resonators and their inverse analogues.

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  • Merbold, Hannes; Bitzer, Andreas; Feurer, Thomas (2011): Near-field investigation of induced transparency in similarly oriented double split-ring resonators. In: Optics Letters 36 (9), S. 1683-1685. DOI: 10.1364/OL.36.001683

    DOI: https://doi.org/10.1364/OL.36.001683 

    Abstract: We present near-field measurements of an induced transparency behavior using a double split-ring resonator geometry. Mapping the out-of-plane electric field component directly reveals that the induced transparency is linked to an asymmetric mode profile with the subunits oscillating in antiphase. The measurements are compared to complementary numerical simulations, and excellent agreement is found.

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  • Merbold, Hannes; Bitzer, Andreas; Feurer, Thomas (2011): Second harmonic generation based on strong field enhancement in nanostructured THz materials. In: Optics express 19 (8), S. 7262-7273. Online verfügbar unter https://doi.org/10.1364/OE.19.007262, zuletzt geprüft am 18.06.2021

     

    Abstract: The THz response of slit structures and split-ring resonators (SRRs) featuring extremely small gaps on the micro- or nanoscale is investigated numerically. Both structures exhibit strong field enhancement in the gap region due to light-induced current flows and capacitive charging across the gap. Whereas nanoslits allow for broadband enhancement the resonant behavior of the SRRs leads to narrowband amplification and results in significantly higher field enhancement factors reaching several 10,000. This property is particularly beneficial for the realization of nonlinear THz experiments which is exemplarily demonstrated by a second harmonic generation process in a nonlinear substrate material. Positioning nanostructures on top of the substrate is found to result in a significant increase of the generation efficiency for the frequency doubled component.

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  • 2009

  • Bitzer, Andreas; Merbold, Hannes; Thoman, Andreas; Feurer, Thomas; Helm, Hanspeter; Walther, Markus (2009): Terahertz near-field imaging of electric and magnetic resonances of a planar metamaterial. In: Optics express 17 (5), S. 3826-3834. Online verfügbar unter https://doi.org/10.1364/OE.17.003826, zuletzt geprüft am 18.06.2021

     

    Abstract: Experimental investigations of the microscopic electric and in particular the magnetic near-fields in metamaterials remain highly challenging and current studies rely mostly on numerical simulations. Here we report a terahertz near-field imaging approach which provides spatially resolved measurements of the amplitude, phase and polarization of the electric field from which we extract the microscopic magnetic near-field signatures in a planar metamaterial constructed of split-ring resonators (SRRs). In addition to studying the fundamental resonances of an individual double SRR unit we further investigate the interaction with neighboring elements.

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  • Bitzer, Andreas; Wallauer, Jan; Helm, Hanspeter; Merbold, Hannes; Feurer, Thomas; Walther, Markus (2009): Lattice modes mediate radiative coupling in metamaterial arrays. In: Optics express 17 (24), S. 22108-22113. Online verfügbar unter https://doi.org/10.1364/OE.17.022108, zuletzt geprüft am 18.06.2021

     

    Abstract: We show that a resonant response with very high quality factors can be achieved in periodic metamaterials by radiatively coupling their structural elements. The coupling is mediated by lattice modes and can be efficiently controlled by tuning the lattice periodicity. Using a recently developed terahertz (THz) near-field imaging technique and conventional far-field spectroscopy together with numerical simulations we pinpoint the underlying mechanisms. In the strong coupling regimes we identify avoided crossings between the plasmonic eigenmodes and the diffractive lattice modes.

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