Near-field Enhanced Optomechanical NAnoresonators – NEONA

• Applicants: Professor Dr.-Ing. Dirk Plettemeier; Dr.-Ing. Danny Reuter
• Subject Area: Communication Technology and Networks, High-Frequency Technology and Photonic Systems, Signal Processing and Machine Learning for Information Technology ; Synthesis and Properties of Functional Materials
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 512904458

Coherent acoustic vibrations in plasmomechanical nanoresonators with frequencies up to the terahertz range are an important feature in terms of ultra-small and highly integrable all-optical RF signal generators. The associated ultrafast modulation of intrinsic dielectric properties allows direct feedback to characteristic features such as localized surface plasmon resonances and their highly pronounced extinction behavior.A meaningful integration of this feature into plasmonic systems compatible with modern silicon photonics has not been realized to date for several reasons: (i) Both optical and mechanical losses are comparatively high in typically top-down fabricated nanostructures. (ii) The achievable depth of spectral modulation is currently limited due to size-related effects. (iii) High frequency modulation is only possible in plasmonic nanostructures such as noble metallic nanoparticles with sufficiently small sizes and is therefore only suitable for the UV / VIS spectral range.This research proposal focuses on near-field coupled double-resonant plasmomechanical nanoresonators to be optimized for the NIR spectral range. This way, the associated spectral hybridization of the intrinsic localized surface plasmon resonances realizes a flexible adaptation of spectral as well as mechanical properties. In contrast to isolated nanostructures, high-frequency modulation of the spectral properties combined with a significant enhancement will be realized by exploiting the electromagnetic interparticle near-field coupling and its directed modulation.This approach requires interparticle distances in the range of ~10 nm which is a challenge for classical top-down manufacturing processes. Bottom-up methods are more practical in terms of the required precision and also more advantageous in terms of significantly lower optical and mechanical losses. For this reason, DNA origami self-assembly of wet-chemically synthesized single-crystalline nanoparticles will be applied. To achieve a meaningful use of the assembled nanoresonators in integrated nanophotonics, a selectively positioned immobilization from the wet phase has to be realized. For this purpose, a thin-film system will be developed that enables topographically assisted surface immobilization.For this project, two groups with strong background in nanostructure design and characterization (TU Dresden, Chair for RF and Photonics Engineering) as well as with great expertise in nanostructure and microelectronic manufacturing (TU Chemnitz, Opto-electronic Systems) team up. Combining the experience, the envisioned all-optical enhanced modulation behavior as well as the realization of optical metasurfaces will be tackled. Supported by comprehensive analyses of the spectral and dynamic properties of the individual nanostructures as well as in the composite, and the optimized fabrication process, important contributions to the understanding of novel highly integrated optical nanodevices are achieved.

• DFG Programme: Research Grants