Periodic Reporting for period 3 - POSEIDON (NanoPhOtonic devices applying SElf-assembled colloIDs for novel ON-chip light sources)
Berichtszeitraum: 2022-07-01 bis 2023-12-31
The aim of POSEIDON is to develop a radically new bottom-up approach towards multi-scale, on chip self-assembly of active colloids based on low-cost colloidal technology. For the first time this encompasses the entire process chain of computer-aided design, controlled synthesis, hierarchical assembly, optoelectronic integration and device fabrication. By controlling and designing self-assembly processes directly on a device, addressing length scales from nm to 100’s of μm simultaneously, the vision of POSEIDON is to allow the fabrication of functional nanophotonic components with 3D, single-nm resolution integrated into complex photonic integrated circuits (PICs). The final goal of POSEIDON is to develop electrically pumped light sources which can be monolithically integrated into the back-end-of-line of CMOS chips. So far, the key bottleneck that is holding back integrated photonic applications is the lack of a monolithically integrable, mass-manufacturable light source as Si does not emit light efficiently. Despite impressive recent progress, the top-down approaches of heterogeneous integration of III-V light sources are costly, have low integration density and low throughput, creating massive cost and complexity barriers for the commercialization of Si photonics. Packaging costs including fibers for external light sources currently constitute around 80% of the total cost of Si photonic PICs and are hence a showstopper. The breakthrough targeted by POSEIDON overcomes these limitations. The developed technology will enable further applications from optical computing, to quantum optics for ultra-secure communications, to personalized health monitoring devices able to detect molecules at ultralow concentrations.
The aim of POSEIDON is to develop a radically new approach towards multi-length-scale, on-chip assembly of active colloids for the creation of optically and electrically pumped on-chip light sources. During the project the structures under investigation have been narrowed down, favoring nanoparticle on mirror (NPoM) and disk-on-disk (DoD) resonators over zero refractive index metamaterials (ZIM).
The aim of POSEIDON is to develop a radically new approach towards multi-length-scale, on-chip assembly of active colloids for the creation of optically and electrically pumped on-chip light sources. During the project the structures under investigation have been narrowed down, favoring nanoparticle on mirror (NPoM) and disk-on-disk (DoD) resonators over zero refractive index metamaterials (ZIM).
WP1 "Theoretical design of colloidal light sources": the roadmap of nanoantennas for the light source was selected and continuously updated. Initial activity focused on nanorod gap antennas providing the highest plasmonic enhancement. Different experimental methods to assemble such structures have been investigated in WP3, in good agreement with simulations from WP1. Different particles to create ZIMs have been screened theoretically in WP1 and filtered based on the experimental results in WP2. The verdict is that the ZIMs we can possibly fabricate are too large for waveguide integration. We have thus focused on NPoM and DoD emitters for WP5 and performed a systematic study of these configurations in WP1.
WP2 "Synthesis of colloidal building blocks": Development of particle synthesis protocols for polystyrene and PDVB laytex particles by miniemulsion and classical emulsion polymerization was completed. Synthesis of new RAFT polymers from different monomer systems for modification of quantum dots (QDs) and gold (Au) nanoparticles (NPs) were completed. Modification of QDs with RAFT polymer for particle transfer from organic apolar to aqueous medium was successful. Synthesis of highly monodisperse metal nanoparticles with tunable size and morphology for nanoantenna light sources was completed, including new bipyramid particles.
WP3: "Integrated assembly of colloidal light sources" included the theoretical design of such materials, including core-shell particles. Different NPoM and DoD configurations fabricated achieved enhancement factors of 4 to 40 compared to references based on pure QDs. Of particular interest are regular arrays of Au nano-crescents on Au mirrors, as their partially broken symmetry allows chiral light-matter interaction.
WP4 "Creation of electrically pumped light source": Fabrication and characterization of electrically pumped emitters in NPoM configurations with CdS/CdSe QDs for visible emission. Due to strong field enhancement in the nm gap between the metals the emission was strongly enhanced, leading to the first observation of light from a single nanocavity. These emitters are candidates for single photon emitters and have been tested correspondingly. The durability of these emitters was increased from 20 s to 40 mins.
WP5 "Creation and optimization of PIC": A theoretical quantitative comparison of light-waveguide coupling for different configurations was optimized, guided by experiments. NPoM and DoD emitters have been integrated on silicon nitride PICs. Compared to references based on pure QDs, enhancements of the photoluminescence coupled to the waveguide have been measured: ~20 times for NPoM emitters and ~40 times for DoD emitters. The recorded output power through the waveguide was 50 pW to 0.5 nW and can be scaled up with stronger excitation, as the estimated efficiencies are 0.01% to 0.2%.
WP6: Dissemination & Exploitation: The POSEIDON results were disseminated up to now via 36 scientific publications, 7000 visitors to the homepage, 288 followers on LinkedIn and more. Noteworthy highlights are the organization of a workshop on the “Integration of novel materials into silicon photonics”, the creation of a “research highlights” section on the POSEIDON homepage aiming at the general public and the podcast series “In her shoes”, aiming at promoting women in science.
WP7: Project Management & coordination: the coordination of such a multidisciplinary project with 8 partners and 4 years duration is a major effort. Overall the organization was smooth due to regular meetings at different levels and clearly defined internal rules and procedures. Regular discussions with the industrial External Advisory Board helped further to successfully steer the project.
WP2 "Synthesis of colloidal building blocks": Development of particle synthesis protocols for polystyrene and PDVB laytex particles by miniemulsion and classical emulsion polymerization was completed. Synthesis of new RAFT polymers from different monomer systems for modification of quantum dots (QDs) and gold (Au) nanoparticles (NPs) were completed. Modification of QDs with RAFT polymer for particle transfer from organic apolar to aqueous medium was successful. Synthesis of highly monodisperse metal nanoparticles with tunable size and morphology for nanoantenna light sources was completed, including new bipyramid particles.
WP3: "Integrated assembly of colloidal light sources" included the theoretical design of such materials, including core-shell particles. Different NPoM and DoD configurations fabricated achieved enhancement factors of 4 to 40 compared to references based on pure QDs. Of particular interest are regular arrays of Au nano-crescents on Au mirrors, as their partially broken symmetry allows chiral light-matter interaction.
WP4 "Creation of electrically pumped light source": Fabrication and characterization of electrically pumped emitters in NPoM configurations with CdS/CdSe QDs for visible emission. Due to strong field enhancement in the nm gap between the metals the emission was strongly enhanced, leading to the first observation of light from a single nanocavity. These emitters are candidates for single photon emitters and have been tested correspondingly. The durability of these emitters was increased from 20 s to 40 mins.
WP5 "Creation and optimization of PIC": A theoretical quantitative comparison of light-waveguide coupling for different configurations was optimized, guided by experiments. NPoM and DoD emitters have been integrated on silicon nitride PICs. Compared to references based on pure QDs, enhancements of the photoluminescence coupled to the waveguide have been measured: ~20 times for NPoM emitters and ~40 times for DoD emitters. The recorded output power through the waveguide was 50 pW to 0.5 nW and can be scaled up with stronger excitation, as the estimated efficiencies are 0.01% to 0.2%.
WP6: Dissemination & Exploitation: The POSEIDON results were disseminated up to now via 36 scientific publications, 7000 visitors to the homepage, 288 followers on LinkedIn and more. Noteworthy highlights are the organization of a workshop on the “Integration of novel materials into silicon photonics”, the creation of a “research highlights” section on the POSEIDON homepage aiming at the general public and the podcast series “In her shoes”, aiming at promoting women in science.
WP7: Project Management & coordination: the coordination of such a multidisciplinary project with 8 partners and 4 years duration is a major effort. Overall the organization was smooth due to regular meetings at different levels and clearly defined internal rules and procedures. Regular discussions with the industrial External Advisory Board helped further to successfully steer the project.
The project is expected to create new applications and markets and reinforce the leadership of European scientific and industrial players in the fields of e.g. optical communication, sensing and point-of-care medicine.
During the last two decades, integrated photonics based on silicon photonics have gained a lot of interest in research and industry developments. The rapid increase of data traffic makes drastic changes to more efficient technologies like full optical data transmission necessary. Recent developments in optical communication mainly rely on hybrid integration of III-V lasers on top of silicon photonics platforms. This procedure is not only costly in terms of III-V wafers and processing, but especially the hybrid assembly can reach up to 80% of the fabrication cost. Large scale integration of efficient (laser) light sources would open the field to many new applications such as point of care medicine, environmental sensing as well as quantum photonics. POSEIDON has evaluated different approaches for colloidal assembly focused on the integration on photonic chips. The focus was put on extracting maximum performance of localized emitters via plasmonic enhancements. The highlight result of 40 times more light in the waveguide compared to references demonstrates the potential of this technology. By defining ways to integrate light emitting materials efficiently onto the photonic platform, POSEIDON paves the route to a new age of photonic integrated circuits.
During the last two decades, integrated photonics based on silicon photonics have gained a lot of interest in research and industry developments. The rapid increase of data traffic makes drastic changes to more efficient technologies like full optical data transmission necessary. Recent developments in optical communication mainly rely on hybrid integration of III-V lasers on top of silicon photonics platforms. This procedure is not only costly in terms of III-V wafers and processing, but especially the hybrid assembly can reach up to 80% of the fabrication cost. Large scale integration of efficient (laser) light sources would open the field to many new applications such as point of care medicine, environmental sensing as well as quantum photonics. POSEIDON has evaluated different approaches for colloidal assembly focused on the integration on photonic chips. The focus was put on extracting maximum performance of localized emitters via plasmonic enhancements. The highlight result of 40 times more light in the waveguide compared to references demonstrates the potential of this technology. By defining ways to integrate light emitting materials efficiently onto the photonic platform, POSEIDON paves the route to a new age of photonic integrated circuits.