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    Ultrafast, Nonlinear and Quantum Optics

    Date:
    29
    Monday
    May
    2023
    -
    31
    Wednesday
    May
    2023
    Conference
    Time: 08:00
    Location: The David Lopatie Conference Centre
    Organizer: Crown Photonics Center
    Contact: talia.tzahor@weizmann.ac.il
    Ultrafast, Nonlinear and Quantum Optics Conference website

    "Molecules in a Quantum-Optical Flask"

    Date:
    25
    Wednesday
    January
    2023
    Lecture / Seminar
    Time: 11:00-12:00
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Dr. Tal Schwartz
    Organizer: Department of Molecular Chemistry and Materials Science
    Contact: ana.naamat@weizmann.ac.il
    Abstract: "Molecules in a Quantum-Optical Flask" When confined to small dimensions, the ... Read more "Molecules in a Quantum-Optical Flask" When confined to small dimensions, the interaction between light and matter can be enhanced up to the point where it overcomes all the incoherent, dissipative processes. In this "strong coupling" regime the photons and the material start to behave as a single entity, having its own quantum states and energy levels. In this talk I will discuss how such cavity-QED effects can be used in order to control material properties and molecular processes. This includes, for example, modifying photochemical reactions [1], enhancing excitonic transport up to ballistic motion close to the light-speed [2-3] and potentially tailoring the mesoscopic properties of organic crystals, by hybridizing intermolecular vibrations with electromagnetic THz fields [4-5]. 1. J. A. Hutchison, T. Schwartz, C. Genet, E. Devaux, and T. W. Ebbesen, "Modifying Chemical Landscapes by Coupling to Vacuum Fields," Angew. Chemie Int. Ed. 51, 1592 (2012). 2. G. G. Rozenman, K. Akulov, A. Golombek, and T. Schwartz, "Long-Range Transport of Organic Exciton-Polaritons Revealed by Ultrafast Microscopy," ACS Photonics 5, 105 (2018). 3. M. Balasubrahmaniyam, A. Simkovich, A. Golombek, G. Ankonina, and T. Schwartz, "Unveiling the mixed nature of polaritonic transport: From enhanced diffusion to ballistic motion approaching the speed of light," arXiv:2205.06683 (2022). 4. R. Damari, O. Weinberg, D. Krotkov, N. Demina, K. Akulov, A. Golombek, T. Schwartz, and S. Fleischer, "Strong coupling of collective intermolecular vibrations in organic materials at terahertz frequencies," Nat. Commun. 10, 3248 (2019). 5. M. Kaeek, R. Damari, M. Roth, S. Fleischer, and T. Schwartz, "Strong Coupling in a Self-Coupled Terahertz Photonic Crystal," ACS Photonics 8, 1881 (2021).
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    “Intelligentsia of Nano-Architected Hierarchical Materials”

    Date:
    27
    Tuesday
    December
    2022
    Lecture / Seminar
    Time: 11:15-12:15
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Prof. Julia Greer
    Organizer: Department of Molecular Chemistry and Materials Science
    Contact: ana.naamat@weizmann.ac.il
    Abstract: Creation of reconfigurable and multi-functional materials can be achieved by inc ... Read more Creation of reconfigurable and multi-functional materials can be achieved by incorporating architecture into material design. In our research, we design and fabricate three-dimensional (3D) nano-architected materials that can exhibit superior and often tunable thermal, photonic, electrochemical, biochemical, and mechanical properties at extremely low mass densities (lighter than aerogels), which renders them useful and enabling in technological applications. Dominant properties of such meta-materials are driven by their multi-scale nature: from characteristic material microstructure (atoms) to individual constituents (nanometers) to structural components (microns) to overall architectures (millimeters and above). Our research is focused on fabrication and synthesis of nano- and micro-architected materials using 3D lithography, nanofabrication, and additive manufacturing (AM) techniques, as well as on investigating their mechanical, biochemical, electrochemical, electromechanical, and thermal properties as a function of architecture, constituent materials, and microstructural detail. Additive manufacturing (AM) represents a set of processes that fabricate complex 3D structures using a layer-by-layer approach, with some advanced methods attaining nanometer resolution and the creation of unique, multifunctional materials and shapes derived from a photoinitiation-based chemical reaction of custom-synthesized resins and thermal post-processing. A type of AM, vat polymerization, has allowed for using hydrogels as precursors, and exploiting novel material properties, especially those that arise at the nano-scale and do not occur in conventional materials. The focus of this talk is on additive manufacturing via vat polymerization and function-containing chemical synthesis to create 3D nano- and micro-architected metals, ceramics, multifunctional metal oxides (nano-photonics, photocatalytic, piezoelectric, etc.), and metal-containing polymer complexes, etc., as well as demonstrate their potential in some real-use biomedical, protective, and sensing applications. I will describe how the choice of architecture, material, and external stimulus can elicit stimulus-responsive, reconfigurable, and multifunctional response
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    "Ultrafast charge transfer in heterostructures of two-dimensional materials"

    Date:
    23
    Tuesday
    August
    2022
    Lecture / Seminar
    Time: 11:00-12:00
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Prof. Giulio Cerullo
    Organizer: Department of Molecular Chemistry and Materials Science
    Contact: ana.naamat@weizmann.ac.il
    Abstract: Heterostructures (HS) of two-dimensional materials offer unlimited possibilit ... Read more Heterostructures (HS) of two-dimensional materials offer unlimited possibilities to design new materials for applications to optoelectronics and photonics. In such HS the electronic structure of the individual layers is well retained because of the weak interlayer van der Waals coupling. Nevertheless, new physical properties and functionalities arise beyond those of their constituent blocks, depending on the type and the stacking sequence of layers. In this presentation we use high time resolution ultrafast transient absorption (TA) and two-dimensional electronic spectroscopy (2DES) to resolve the interlayer charge scattering processes in HS. We first study a WSe2/MoSe2 HS, which displays type II band alignment with a staggered gap, where the valence band maximum and the conduction band minimum are in the same layer. By two-colour pump-probe spectroscopy, we selectively photogenerate intralayer excitons in MoSe2 and observe hole injection in WSe2 on the sub-picosecond timescale, leading to the formation of interlayer excitons (ILX). The temperature dependence of the build-up and decay of interlayer excitons provide insights into the layer coupling mechanisms [1]. By tuning into the ILX emission band, we observe a signal which grows in on a 400 fs timescale, significantly slower than the interlayer charge transfer process. This suggests that photoexcited carriers are not instantaneously converted into the ILX following interlayer scattering, but that rather an intermediate scattering processes take place We then perform 2DES, a method with both high frequency and temporal resolution, on a large-area WS2/MoS2 HS where we unambiguously time resolve both interlayer hole and electron transfer with 34 ± 14 and 69 ± 9 fs time constants, respectively [2]. We simultaneously resolve additional optoelectronic processes including band gap renormalization and intralayer exciton coupling. Finally, we investigate a graphene/WS2 HS where, for excitation well below the bandgap of WS2, we observe the characteristic signal of the A and B excitons of WS2, indicating ultrafast charge transfer from graphene to the semiconductor [3]. The nonlinear excitation fluence dependence of the TA signal reveals that the underlying mechanism is hot electron/hole transfer, whereby a tail the hot Fermi-Dirac carrier distribution in graphene tunnels through the Schottky barrier. Hot electron transfer is promising for the development of broadband and efficient low-dimensional photodetectors. [1] Z. Wang et al., Nano Lett. 21, 2165–2173 (2021). [2] V. Policht et al., Nano Lett. 21, 4738–4743 (2021). [3] C. Trovatello et al., npj 2D Mater Appl 6, 24 (2022).
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    WIS-Q Seminar

    Date:
    12
    Thursday
    May
    2022
    Lecture / Seminar
    Time: 12:30-14:30
    Title: Photonic Route to Fault-tolerant Quantum Computing
    Location: Nella and Leon Benoziyo Physics Library
    Lecturer: Barak Dayan
    Organizer: Department of Condensed Matter Physics
    Contact: inna.dombrovsky@weizmann.ac.il
    Abstract: I will describe the photonic approach to quantum computation, which is the only ... Read more I will describe the photonic approach to quantum computation, which is the only technology that has been originally designed to reach the massive scaling required for fault- tolerant universal computation (> 106 physical qubits). It combines topological error correction and measurement-based quantum computation, with the leading effort relying on massive-scale silicon photonics. I will then describe how cavity-QED with single atoms allows deterministic photon-atom two qubit gates, which in turn can drastically simplify the road towards fault-tolerant photonic quantum computing and improve its scaling to even larger numbers of physical qubits.
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    AMOS special seminar

    Date:
    16
    Thursday
    December
    2021
    Lecture / Seminar
    Time: 11:00-12:00
    Title: Engineering quantum processors and quantum networks atom-by-atom
    Location: Edna and K.B. Weissman Building of Physical Sciences
    Lecturer: Prof. Hannes Bernien
    Organizer: Crown Photonics Center
    Contact: tamar.fuchs@weizmann.ac.il
    Details: 10:45: Coffee, tea and more...
    Abstract: Reconfigurable arrays of neutral atoms are an exciting new platform to study qua ... Read more Reconfigurable arrays of neutral atoms are an exciting new platform to study quantum many-body phenomena and quantum information protocols. Their excellent coherence combined with programmable Rydberg interactions have led to intriguing observations such as quantum phase transitions, the discovery of quantum many-body scars, and the recent realization of a topological spin liquid phase. Here, I will introduce new methods for controlling and measuring atom arrays that open up new directions in quantum state control, quantum feedback, and many-body physics. First, I will introduce a dual species atomic array in which the second atomic species can be used to measure and control the primary species. This will lead to the possibility of performing quantum nondemolition measurements and new ways of engineering large, entangled states on these arrays. Furthermore, prospects of studying open systems with engineered environments will be discussed. An alternative, hybrid approach for engineering interactions and scaling these quantum systems is the coupling of atoms to nanophotonic structures in which photons mediate interactions between atoms. Such a system can function as the building block of a large-scale quantum network. In this context, I will present quantum network node architectures that are capable of long-distance entanglement distribution at telecom wavelengths.
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    Emergence of Complexity in Chiral Nanostructures

    Date:
    11
    Monday
    October
    2021
    Colloquium
    Time: 11:00-12:00
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Prof. Nicholas A. Kotov
    Organizer: Faculty of Chemistry
    Contact: sarah.amzallag@weizmann.ac.il
    Abstract: The structural complexity of composite biomaterials and biomineralized particles ... Read more The structural complexity of composite biomaterials and biomineralized particles arises from the hierarchical ordering of inorganic building blocks over multiple scales. While empirical observations of complex nanoassemblies are abundant, physicochemical mechanisms leading to their geometrical complexity are still puzzling, especially for non-uniformly sized components. These mechanisms are discussed in this talk taking an example of hierarchically organized particles with twisted spikes and other morphologies from polydisperse Au-Cys nanoplatelets [1]. The complexity of these supraparticles is higher than biological counterparts or other complex particles as enumerated by graph theory (GT). Complexity Index (CI) and other GT parameters are applied to a variety of different nanoscale materials to assess their structural organization. As the result of this analysis, we determined that intricate organization Au-Cys supraparticles emerges from competing chirality-dependent assembly restrictions that render assembly pathways primarily dependent on nanoparticle symmetry rather than size. These findings open a pathway to a large family of colloids with complex architectures and unusual chiroptical and chemical properties. The GT-based design principles for complex chiral nanoassemblies are extended to engineer drug discovery platforms for Alzheimer syndrome [3], materials for chiral photonics, vaccines, and antivirals. Developed GT methods were applied to the design of complex biomimetic composites for energy and robotics applications [2,4] will be shown as a nucleus for discussions. References [1] W. Jiang, Z.-B. et al, Emergence of Complexity in Hierarchically Organized Chiral Particles, Science, 2020, 368, 6491, 642-648. [2] Wang, M.; Vecchio, D.; et al Biomorphic Structural Batteries for Robotics. Sci. Robot. 2020, 5 (45), eaba1912. https://doi.org/10.1126/scirobotics.aba1912. [3] Jun Lu, et al, Enhanced optical asymmetry in supramolecular chiroplasmonic assemblies with long-range order, Science, 2021, 371, 6536, 1368 [4] D. Vecchio et al, Structural Analysis of Nanoscale Network Materials Using Graph Theory, ACS Nano 2021, 15, 8, 12847–12859.
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