Nonlinear and ultrafast optical response of metamaterial-inspired dielectric waveguides hybridized with monolayer transition metal dichalcogenides

• Applicant: Professorin Dr. Isabelle Staude
• Subject Area: Experimental Condensed Matter Physics ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 448835038

Mie-resonant dielectric nanostructures have been established as an efficient platform for enhancing nonlinear-optical frequency generation and ultrafast all-optical tuning effects. However, so far dielectric Mie resonators and their capabilities for enhancing light-matter interactions have been mainly explored for individual nanoresonators or in a metasurface geometry, i.e. in planar two-dimensional arrangements of many such nanoresonators. Their deployment in technologically relevant on-chip waveguide architectures, in contrast, remains largely unexplored. Metamaterial-inspired resonant waveguides consisting of chains of Mie-resonant nanoparticles offer important opportunities for enhancing the performance of future integrated photonic devices. In particular, while providing favorable transmission properties, the optical field confinement supported by the nanoresonators is expected to allow for significantly enhancing nonlinear optical effects required for on-chip active photonic devices. In this project, we wish to combine custom-designed Mie-resonant dielectric waveguides with two-dimensional transition metal dichalcogenides (2D-TMDs), which are known for their strong linear and nonlinear optical response and favorable electro-optical and ultrafast all-optical tuning properties. The project comprises the design, fabrication, and optical characterization of the hybrid Mie-resonant waveguide systems, targeting the efficient active control of light on a chip. In particular, we will focus on three main mutually interrelated tasks, namely (i) the effective nonlinear light conversion, in particular second-harmonic generation, on a chip by hybrid Mie-resonant dielectric waveguides coupled to 2D-TMDs, (ii) the ultrafast all-optical modulation of light guided through the waveguide structures, and (iii) the electro-optical control of the proposed waveguides as well as of the nonlinear effects shown in the first task. Regarding the employed materials, for the waveguides we will concentrate on silicon and silicon nitride as two dielectric materials, which are both well-established materials for on-chip integrated optics and have sufficiently high refractive index to support strong Mie-type resonances in corresponding nanoparticles. For the 2D-TMDs, we will use monolayer crystals, grown by the scalable approach of chemical vapor deposition. The Mie-resonant waveguide structures are expected to strongly enhance the light-matter interaction with the 2D-TMDs by two distinct mechanisms: On the one hand, for a suitable structure design, they can concentrate the electromagnetic near-fields in the 2D-TMDs. On the other hand, they can increase the interaction length with the ultra-thin 2D-TMD by propagation in the hybrid resonant waveguide. The fundamental investigation of these physical mechanisms in the hybrid resonant waveguide structures and their application to demonstrate a range of active nanophotonic structures on a chip is at the heart of this project.

• DFG Programme: Research Grants
• International Connection: Russia
• Partner Organisation: Russian Foundation for Basic Research, until 3/2022
• Cooperation Partner: Dr. Andrey Fedyanin, until 3/2022