Nanotechnology in Optoelectronics

Nanophotonic structures are a foundation for the growing field of light-based quantum networks and devices enabled by their ability to couple with and manipulate photons. Colloidal quantum dots (QDs) are uniquely suited to complement this range of devices due to their solution-processability, broad tunability, and near-unity photoluminescence quantum yields in some cases. To bridge the gap between them, electrohydrodynamic inkjet (EHDIJ) printing serves as a highly precise and scalable nanomanufacturing method for deterministic positioning and deposition of attoliter-scale QD droplets. This includes heterointegration in devices that are challenging to create by conventional subtractive semiconductor processing, such as QDs emitters coupled to substrate-decoupled nanoscale resonant structures. In a recent paper published in Advanced Material Technologies, we demonstrated the first successful application of EHDIJ printing for the integration of these colloidal QDs into suspended nanophotonic cavities, achieving selective single-cavity deposition for cavity pairs as close as 100 nm apart. These results motivate the development of future suspended hetero-integrated devices that utilize EHDIJ printing as a sustainable, additive, and scalable method for quantum photonics nanomanufacturing. The paper can be found at: https://lnkd.in/ggPS6wuC

ACTIVELY TUNABLE EXCITONIC METASURFACES THAT TRAP LIGHT INSIDE THEMSELVES Controlling light at the nanometer scale remains a central challenge in photonics. While conventional optics relies on bulky refractive elements, modern nanophotonic platforms use metasurfaces—ultrathin, subwavelength optical coatings capable of sculpting wavefronts with remarkable precision. Yet most metasurfaces are fundamentally static: once fabricated, their optical response cannot be electrically tuned or dynamically reconfigured. Researchers at the University of Amsterdam have now overcome this limitation by creating an actively tunable excitonic metasurface that traps light within itself and can be electrically switched on and off. The device integrates a monolayer of tungsten disulfide (WS₂)—a two‑dimensional semiconductor with exceptionally strong exciton resonances—with a non‑local dielectric metasurface engineered to confine and enhance the electromagnetic field exactly where the WS₂ resides. When WS₂ absorbs light, it forms tightly bound electron–hole pairs known as excitons, whose optical signatures dominate even at room temperature. These excitons are highly sensitive to charge density, making them ideal for electrical modulation—provided the exciton–photon interaction is sufficiently strong. The metasurface accomplishes this by trapping light in guided‑mode resonances, dramatically amplifying the local field and strengthening exciton–photon coupling. A gold (Au) back‑gate plays a decisive role in enabling active tunability. Applying a voltage between the Au gate and the WS₂ monolayer induces strong electron doping, which increases exciton–electron (Coulomb) scattering and efficiently quenches the A‑exciton transition. This gating mechanism suppresses excitonic photoluminescence at 618 nm by 108×, while leaving the trion peak largely unchanged—an unprecedented level of room‑temperature exciton control previously achievable only at cryogenic conditions. The Au back‑gate is therefore essential for driving the metasurface between the strong‑ and weak‑coupling regimes that underpin its modulation behavior. Experimentally, the hybrid‑2D metasurface achieves 9.9 dB reflectance modulation, a fivefold improvement over prior excitonic devices. The modulation arises from a continuous, voltage‑controlled transition in the exciton’s nonradiative decay rate, demonstrating robust, electrically tunable exciton–photon coupling in free space. By uniting pristine 2D excitonic materials, non‑local dielectric metasurfaces, and Au‑enabled charge control, this platform establishes a new class of ultracompact, room‑temperature optical modulators. It opens the door to active wavefront shaping, free‑space optical communication, LiDAR, and photonic information processing—marking a significant step toward fully reconfigurable nanophotonic systems. #https://lnkd.in/e7GUyrzG

📣 Exciting News! 📚🎉 Extremely happy to share our latest paper on "Valley-addressable monolayer lasing at room-temperature" has been published in Science!! 🎉🎉 🔍 Herein, we've pushed the boundaries of atomic-scale spin-optics, drawing inspiration from the emergence of valley pseudo-spins within 2D monolayers. Our work unveils the successful integration of a monolayer transition metal dichalcogenides with a carefully designed photonic crystal cavity resulting in lasing with valley-addressable polarized output. Operation at room temperature without the need for a magnetic field should be useful for quantum sensing, quantum encryption and angular momentum–based communications, marking a transformative leap forward in the world of advanced nanophotonic technology development. 🌟 🔗 You can access the publication here: I extend my sincere gratitude to Prof. Erez Hasman, Kexiu Rong, Xiaoyang Duan, and Prof. Elad Koren, from Technion - Israel Institute of Technology for their incessant effort to refine the project and give me the invaluable opportunity to contribute to this captivating endeavor. Department of Materials Science and Engineering -Technion Russell Berry Institute for Nanotechnology in the Technion (#RBNI) Micro & Nano Fabrication Unit #Helen Diller quantum center at Technion Science Magazine AAAS Group #2dmaterials #monolayer #WS2 #microcavity #photonic crystal (#PhC) #quantumtechnology #nanoscience #devices #physics #materialsscience

How can we control light at the nanoscale—without changing the structure we've already fabricated? In our latest work published today in Nature Photonics, we demonstrate that CrSBr, a 2D quantum magnet with antiferromagnetic order, enables dynamic and strong tuning of exciton-polaritonic resonances in photonic crystal slabs using an external magnetic field. This is one of the first realizations of a monolithic, in situ tunable nanophotonic device based entirely on a 2D quantum magnet, opening new directions at the intersection of nanophotonics and quantum materials. Led by Ahmet Kemal Demir and Luca Nessi, this work was a fantastic collaboration between the groups of Marin Soljacic and Riccardo Comin at MIT. Link to the article: https://lnkd.in/evTnX2Sq

Quantum Breakthrough: New Dots Emit Photons 3x Faster for Next-Gen Networks Introduction A new fabrication method for quantum dots is significantly improving the speed, precision, and usability of single-photon sources—critical components for quantum communication and photonic computing systems. Key Breakthrough Improved Quantum Dot Design Researchers created low-density, highly symmetrical quantum dots Enables easier isolation of single-photon emitters Reduces noise and structural defects common in conventional methods Faster Photon Emission Radiative lifetimes reduced to ~300 picoseconds Approximately 3x faster than traditional quantum dots Improves timing precision for quantum communication systems Manufacturing Innovation Local Droplet Etching Technique Uses metal droplets to form nanocavities during crystal growth Cavities filled with ultra-thin (~1 nm) indium gallium arsenide Minimizes strain and enhances optical performance Low-Density Advantage Surface density reduced to ~0.2–0.3 dots per square micrometer Allows precise control and isolation of individual quantum emitters Enhanced Optical Performance Wavelength Tunability Emission range extended to 780–900 nanometers Better suited for integrated photonic systems with lower signal loss High Structural Symmetry Supports generation of entangled photon pairs Maintains competitive fine structure splitting for quantum applications Strategic Implications Quantum Communication Faster, cleaner photon emission improves data transmission reliability Supports development of secure quantum networks Photonic Quantum Computing Enables scalable, on-demand photon sources for computation Aligns with integrated photonics architectures System Integration Compatibility with existing semiconductor and optical technologies Facilitates transition from lab research to deployable systems Conclusion: Why This Matters This advancement addresses key bottlenecks in quantum photonics by delivering faster, more reliable single-photon sources with improved manufacturability. As quantum networks and photonic computing scale, innovations like these will be foundational in moving from experimental systems to real-world deployment. I share daily insights with tens of thousands of followers across defense, tech, and policy. If this topic resonates, I invite you to connect and continue the conversation. Keith King https://lnkd.in/gHPvUttw

In a recent ACS Nano publication, MSDLab @ Indian Institute of Science discloses how to dynamically control exciton-defect interactions in monolayer WS₂ and how the field drives the oscillator strength redistribution, leading to the dissociation of defect-bound excitons, trions, and charged biexcitons, and an enhancement in the neutral exciton emission. This work bridges key gaps in understanding many-body interactions in 2D TMDs and opens up exciting opportunities in: • Quantum photonics – enabling electro-optic modulation of single-photon emission • On-chip optical modulators – with a practical in-plane field configuration • Photonic integrated circuits – using scalable and waveguide-compatible 2D material architectures Overall, the findings highlight the potential of 2D semiconductors for next-gen quantum communication and tunable optoelectronics. Read the full paper here: https://lnkd.in/gtsatmBy Student Authors: Rupali Verma and Utpreksh Patbhaje #IIScResearch #2Dmaterials #TMD #Excitons #QuantumPhotonics #Optoelectronics #Nanotechnology #ElectroOptic #Photonics #ResearchInnovation #WS2