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Three-Dimensional Nonlinear Chiral Plasmonic Metamaterials

Periodic Reporting for period 1 - 3DNCPM (Three-Dimensional Nonlinear Chiral Plasmonic Metamaterials)

Reporting period: 2015-03-01 to 2017-02-28

The main research objective of the 3DNCPM research is to deepen the understanding of the processes underlying the nonlinear optical responses of three-dimensional (3D) chiral plasmonic metamaterials. The main goal is to investigate the microscopic origins of the nonlinear chiral response, as well as the involved nonlinear generation processes. On the one hand, this will enable to maximize the conversion efficiencies. On the other hand, it will allow the construction of more complex chiral systems with tailored nonlinear optical responses.
To this end, the 3DNCPM project aims at exploiting the state-of-the art metamaterial designs and plasmonic nanometallic structure fabrication technology to answer fundamental questions on the processes underlying the nonlinear optical responses of 3D chiral plasmonic nanostructures. Despite some initial experiments in the field of nonlinear chiral plasmonics, a surprisingly large number of open questions remain. The entanglement of a multitude of different factors such as linear properties, spatial symmetries, changing near-field distributions, the presence of different materials and multiple resonances makes it nearly impossible to deduce the origin of the nonlinear response and the true influence of the individual subsystems. One of the main drawbacks of the conducted experiments, surprisingly, appears to be the complexity of the structures. In particular, planar chiral metamaterials that have mostly been utilized do not present structural variation in the propagation direction, hence giving very small CD signals and any optical activity observed is due to the symmetry breaking owed to the substrate. Three-dimensionality, on the other hand, has the advantage of larger optical activity; therefore, by appropriately designing 3D unit cells, enhancement of the nonlinear optical activity processes can be greatly increased.
The 3DNCPM project contributes to scientific literacy by enhancing public understanding to scientific concepts and processes related to plasmonics and metamaterials nanotechnology. In particular, it engages the public in social conversation, stimulates social interaction and public participation in society by expressing positions that are scientifically and technologically informed through reading with understanding science articles in the popular press, through the participation to Open Science Days and through social networking and the internet. Focus on such subjects creates a critical mass of both human potential and knowledge in the European society that can have direct influence on the technological, sociological and economic development of the EU. Also, specific research outcomes through the 3DNCPM project are expected to stimulate the field of nano-optics, plasmonics, and metamaterials significantly, as they take basic research efforts into the applied world (e.g. for optical, medical and pharmaceutical technologies). Transferring this fundamental knowledge to industry contributes to the advance of industrial innovation and directly transforms the latest scientific findings into added value hence, maximizing the impact of new technologies on jobs and work division as a large proportion of firms would not have developed new products and processes in the absence of academic research.
The research results obtained within the 3DNCPM project demonstrate that Direct Laser Writing in combination with subsequent electroless silver plating is a quite flexible fabrication method for the realization of truly 3D chiral plasmonic metamaterials. By employing the above fabrication approach, the plasmonic version of a 3D chiral meta-atom, which consists of a loop-wire medium, namely the “so-called” twisted omega particle is experimentally realized. The arising chiro-optical spectrum is explained in terms of a single-oscillator model system used classically to describe the generation of natural optical activity in chiral media and the exact plasmonic analogue to the one-electron theory of optical activity is demonstrated.
In addition, within the framework of 3DNCPM project, 3D high-resolution woodpile photonic crystals containing an organic-inorganic silicon-zirconium (Si-Zr) composite and cadmium sulfide (CdS) quantum dots (QDs) are successfully fabricated by combining Direct Laser Writing based on two-photon absorption and in-situ synthesis of CdS nanoparticles inside the 3D photonic matrix. It is demonstrated that the novel CdS-Zr-Si composite material exhibits a high nonlinear refractive index value measured by means of Z-scan method, while the fabricated woodpile structures show clear photonic stop bands in the wavelength region between 1000nm to 450nm.
Exploitation and dissemination of research results:
Scientific Journals:
1) I. Sakellari, X. Yin, M. Nesterov, K. Terzaki, A. Xomalis, and M. Farsari «Three-dimensional Chiral Plasmonic Metamaterials fabricated by Direct Laser Writing: The Twisted Omega Particle», submitted to Advanced Optical Materials (2017)

Conferences:
1) I. Sakellari, E. Kabouraki, D. Gray, M. Vamvakaki, and M. Farsari, «Quantum Dot Based 3D Photonic Devices» (poster), SPIE Photonics West, San Francisco, California, USA (2017)
2) I. Sakellari, E. Kabouraki, D. Gray, M. Vamvakaki, and M. Farsari, «Quantum Dot Based 3D Photonic Devices» (poster), Advanced Architectures in Photonics, Mykonos, Greece (2016)
3) I. Sakellari, X. Yin, M. Nesterov, K. Terzaki, A. Xomalis, M. Farsari, and Harald Giessen «3D Chiral Plasmonic Metamaterials Fabricated by Direct Laser Writing: The Twisted Omega Particle» (oral), Metamaterials'16, Chania, Greece (2016)
4) I. Sakellari, X. Yin, M. Nesterov, K. Terzaki, A. Xomalis, and M. Farsari, «3D Chiral Plasmonic Metamaterials Fabricated by Direct Laser Writing: The Twisted Omega Particle» (oral), META'16, Malaga, Spain (2016)

Conference Proceedings:
1) I. Sakellari, E. Kabouraki, D. Gray, M. Vamvakaki, and M. Farsari, «Quantum Dot Based 3D Photonic Devices», (Proc. SPIE 10115, Advanced Fabrication Technologies for Micro/Nano Optics and Photonics X, 101151A, doi:10.1117/12.2254835 SPIE Photonics West, 2017)
2) I. Sakellari, X. Yin, M. Nesterov, K. Terzaki, A. Xomalis, and M. Farsari, «3D Chiral Plasmonic Metamaterials fabricated by Direct Laser Writing: The Twisted Omega Particle», (Proceedings META'16, 2016)
The 3DNCPM project should not only lead to a fundamental understanding of the nonlinear optical mechanisms that can be enhanced largely by tailoring appropriate plasmonic nanostructures, but also take the functional concepts of nonlinear plasmonics from basic and fundamental research into novel applications in modulation of light intensity and polarization in nanophotonic devices. Companies related to the fields of optics and optoelectronics (e.g. Carl Zeiss) are highly interested in 3D metamaterials as such novel optical devices could be utilized in the field of near-infrared polarization optics or aberration correctors. Additionally, pharmaceutical and medical technology companies are interested in the development of real-world optical sensing concepts for different chemicals; nonlinear metamaterial sensors could serve as highly sensitive probes for exploring molecular chemistry providing a cheap and sensitive solution for this problem.
Twisted omegas by direct laser writing and electroless silver plating