Infrared hybrid and plasmonic silicon photonic circuits

Extension of integrated photonics from the telecommunications band further into the mid-IR is an emerging field with applications in IR detection and imaging systems. Plasmonics, the use of electromagnetic fields at the surface of metals, offers a highly complementary set of capabilities to conventional photonics. Merging of photonic waveguides with plasmonics makes sense in particular for infrared applications as it allows almost unlimited concentration of energy far below the diffraction limit of interest for applications in fast detectors, modulators and sensors. Furthermore, silicon plasmonics is a natural route to photonic and electronic integration, as it enables electrons and photons to interact on mutual terms at the surfaces of metal.

This project aims to extend the range of hybrid photonic and plasmonic components, currently under development for telecommunications applications, to infrared silicon photonics. The photonics platforms under study are SiGe, suspended SOI and Ge waveguides, covering the wavelength range from 2 micron up to >8 micron. The enhancement potential of plasmonics grows dramatically for wavelengths deeper into the mid-IR as the ratio of wavelength to nanofabrication feature size grows. The student will engage with the design and fabrication of components using the state-of-the-art silicon photonics nanofabrication capabilities, and numerical modelling using available commercial software tools. Advanced mid-IR spectroscopy studies will be conducted using available infrared photonics setups using QCL sources, as well as an ultrafast OPO tunable up to 4 micron with home-built pump and probe setup for waveguides.