Tunable On-Chip Meta-Waveguides for Reprogrammable Integrated Optics

• Applicant: Professor Dr. Antonio Calà Lesina
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas ; Computer-Aided Design of Materials and Simulation of Materials Behaviour from Atomic to Microscopic Scale
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 544158178

Integrated optics is based on bringing multiple passive and active optical components, such as waveguides, couplers, modulators, light sources and detectors, onto a single chip. This has enabled the creation of compact and efficient devices which can perform advanced optical operations that traditionally require bulky optics and bench-size set-ups. In the last decade, we have assisted to the emergence of flat-optics, which is replacing many bulky optical devices, such as lenses and polarizers, with nanometrically thin devices, called metasurfaces. These are formed by nanostructures arranged on a surface and provide functionalities not achievable in traditional optical components. Several mechanisms to modify the optical response of metasurfaces have been demonstrated, based on voltage gating, temperature variation, mechanical actuation, chemical reactions, phase change materials, nonlinear effects, and microfluidic channels. Most metasurfaces to date have been demonstrated for propagation in free space. However, metasurfaces have recently been patterned on top or on the facet of waveguides, thus introducing novel functionalities in integrated optics. The proposal combines the expertise of two groups on the simulation and design of tunable metasurfaces (Leibniz University Hannover, Germany) and on the fabrication and analysis of waveguides and metasurfaces on a chip (Ben-Gurion University, Israel). In this project, we will investigate dielectric metasurfaces patterned on the top/facet of lithium niobate waveguides. Tunability of metasurfaces and control of optical signals will be achieved by means of liquid crystals and electro-optic effects. Numerical simulations and inverse designs methods will be exploited to enable functionalities such as tunable polarization control, mode conversion, and non-reciprocal propagation on a chip. The most promising designs will be fabricated and experimentally validated in a setup controllable via software. This will ultimately enable reprogrammable optical chips for possible applications in optical communications, computing, and sensing.

• DFG Programme: Research Grants
• International Connection: Israel
• International Co-Applicant: Professorin Dr. Alina Karabachevsky