08 Fakultät Mathematik und Physik

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/9

Browse

Filters

Settings

Institute: search.filters.UBSInstitut.2. Physikalisches InstitutPublication Type: search.filters.UBSTyp.Zeitschriftenartikel

Search Results

Now showing 1 - 6 of 6
  • Thumbnail Image
    ItemOpen Access
    High space‐bandwidth‐product (SBP) hologram carriers toward photorealistic 3D holography
    (2024) Li, Jin; Li, Xiaoxun; Huang, Xiangyu; Kaissner, Robin; Neubrech, Frank; Sun, Shuo; Liu, Na
    3D holography capable of reproducing all necessary visual cues is considered the most promising route to present photorealistic 3D images. Three elements involving computer‐generated hologram (CGH) algorithms, hologram carriers, and optical systems are prerequisites to create high‐quality holographic displays for photorealistic 3D holography. Especially, the hologram carrier directly determines the holographic display capability and the design of high space‐bandwidth‐product (SBP) optical systems. Currently, two categories of hologram carriers, i.e., spatial light modulators (SLM) and metasurfaces, are regarded as promising candidates for photorealistic 3D holography. However, most of their SBP capability still cannot match the amount of information generated by the CGH. To address this issue, tremendous efforts are made to improve the capability of hologram carriers. Here, the main hologram carriers (from SLM to metasurfaces) that are widely utilized in holography systems to achieve high SBP capability (high resolution, wide viewing angles, and large sizes) are reviewed. The purpose of this review is to identify the key challenges and future directions of SLM‐based and metasurface‐based holography for photorealistic 3D holographic images.
  • Thumbnail Image
    ItemOpen Access
    Dimerization and oligomerization of DNA-assembled building blocks for controlled multi-motion in high-order architectures
    (2021) Xin, Ling; Duan, Xiaoyang; Liu, Na
    In living organisms, proteins are organized prevalently through a self-association mechanism to form dimers and oligomers, which often confer new functions at the intermolecular interfaces. Despite the progress on DNA-assembled artificial systems, endeavors have been largely paid to achieve monomeric nanostructures that mimic motor proteins for a single type of motion. Here, we demonstrate a DNA-assembled building block with rotary and walking modules, which can introduce new motion through dimerization and oligomerization. The building block is a chiral system, comprising two interacting gold nanorods to perform rotation and walking, respectively. Through dimerization, two building blocks can form a dimer to yield coordinated sliding. Further oligomerization leads to higher-order structures, containing alternating rotation and sliding dimer interfaces to impose structural twisting. Our hierarchical assembly scheme offers a design blueprint to construct DNA-assembled advanced architectures with high degrees of freedom to tailor the optical responses and regulate multi-motion on the nanoscale.
  • Thumbnail Image
    ItemOpen Access
    Transformable plasmonic helix with swinging gold nanoparticles
    (2022) Peil, Andreas; Zhan, Pengfei; Duan, Xiaoyang; Krahne, Roman; Garoli, Denis; M. Liz‐Marzán, Luis; Liu, Na
    Control over multiple optical elements that can be dynamically rearranged to yield substantial three‐dimensional structural transformations is of great importance to realize reconfigurable plasmonic nanoarchitectures with sensitive and distinct optical feedback. In this work, we demonstrate a transformable plasmonic helix system, in which multiple gold nanoparticles (AuNPs) can be directly transported by DNA swingarms to target positions without undergoing consecutive stepwise movements. The swingarms allow for programmable AuNP translocations in large leaps within plasmonic nanoarchitectures, giving rise to tailored circular dichroism spectra. Our work provides an instructive bottom‐up solution to building complex dynamic plasmonic systems, which can exhibit prominent optical responses through cooperative rearrangements of the constituent optical elements with high fidelity and programmability.
  • No Thumbnail Available
    ItemOpen Access
    Fullerene: Käfige aus Kohlenstoffatomen mit faszinierenden Eigenschaften
    (1996) Mehring, Michael
    Obwohl zwei der Modifikationen des Kohlenstoffs, nämlich Graphit und Diamant, seit langem bekannt sind, wurde die dritte Modifikation, die Fullerene, erst gegen Ende des 20. Jahrhunderts vor wenigen Jahren entdeckt. Diese Entdeckung war ein Resultat von Grundlagenforschung und interdisziplinärer Kooperation zwischen Chemie und Physik auf dem Gebiet der Cluster. Eine besondere Rolle spielten hierbei auch Vorstellungen von Astrophysikern über interstellaren Staub. Bei der Untersuchung von Kohlenstoffclustern in Molekularstrahlen beobachteten Curl, Kroto, Smalley und Mitarbeiter geschlossene Käfige aus Kohlenstoffatomen der Zusammensetzung Cn, wobei n eine ganze Zahl ist. Hierfür erhielten sie 1996 den Nobelpreis für Chemie. Das herausragendste Molekül war hierbei das C60-Fulleren, das fast die Gestalt einer Kugel besitzt und aus 60 Kohlenstoffatomen besteht. Angeregt durch die Konstruktionen der Kuppelbauten des Architekten Buckminster Fuller, der seine Kuppeln aus Sechsecken und Fünfecken zusammenzusetzen pflegt, gaben Kroto und Mitarbeiter den neuentdeckten Kohlenstoffmolekülen den Namen Buckminsterfullerene, im englischen Sprachgebrauch auch 'Buckyballs' genannt. Heute hat sich der etwas kürzere Name 'Fullerene' durchgesetzt. Einige Jahre später fanden die Astrophysiker Krätschmer, Huffman und Mitarbeiter einen Weg, diese Moleküle in großer Menge zu produzieren. Dabei war ihr Interesse gar nicht, C60 herzustellen, sondern den interstellaren Staub und die Chemie eines Roten Riesen im Labor zu simulieren. Mehr zufällig entdeckten sie im Ruß einer abgebrannten Lichtbogenelektrode einen großen Anteil an C60 (etwa zehn Prozent) und C70 (etwa ein Prozent) sowie höhere Fullerene (0,1 Prozent).
  • Thumbnail Image
    ItemOpen Access
    Stabilizing γ‐MgH2 at nanotwins in mechanically constrained nanoparticles
    (2021) Kammerer, Jochen A.; Duan, Xiaoyang; Neubrech, Frank; Schröder, Rasmus R.; Liu, Na; Pfannmöller, Martin
    Reversible hydrogen uptake and the metal/dielectric transition make the Mg/MgH2 system a prime candidate for solid‐state hydrogen storage and dynamic plasmonics. However, high dehydrogenation temperatures and slow dehydrogenation hamper broad applicability. One promising strategy to improve dehydrogenation is the formation of metastable γ‐MgH2. A nanoparticle (NP) design, where γ‐MgH2 forms intrinsically during hydrogenation is presented and a formation mechanism based on transmission electron microscopy results is proposed. Volume expansion during hydrogenation causes compressive stress within the confined, anisotropic NPs, leading to plastic deformation of β‐MgH2 via (301)β twinning. It is proposed that these twins nucleate γ‐MgH2 nanolamellas, which are stabilized by residual compressive stress. Understanding this mechanism is a crucial step toward cycle‐stable, Mg‐based dynamic plasmonic and hydrogen‐storage materials with improved dehydrogenation. It is envisioned that a more general design of confined NPs utilizes the inherent volume expansion to reform γ‐MgH2 during each rehydrogenation.
  • Thumbnail Image
    ItemOpen Access
    Non-equilibrium work distribution for interacting colloidal particles under friction
    (2015) Gomez-Solano, Juan Ruben; July, Christoph; Mehl, Jakob; Bechinger, Clemens
    We experimentally investigate the non-equilibrium steady-state distribution of the work done by an external force on a mesoscopic system with many coupled degrees of freedom: a colloidal crystal mechanically driven across a commensurate periodic light field. Since this system mimics the spatiotemporal dynamics of a crystalline surface moving on a corrugated substrate, our results show general properties of the work distribution for atomically flat surfaces undergoing friction. We address the role of several parameters which can influence the shape of the work distribution, e.g. the number of particles used to locally probe the properties of the system and the time interval to measure the work. We find that, when tuning the control parameters to induce particle depinning from the substrate, there is an abrupt change of the shape of the work distribution. While in the completely static and sliding friction regimes the work distribution is Gaussian, non-Gaussian tails show up due to the spatiotemporal heterogeneity of the particle dynamics during the transition between these two regimes.