What
The goal of the project is to study the integration of 2D materials together with plasmonic waveguides for use as efficient direct on-chip light sources with applications such as biosensing and photonic integrated circuits (PICs). Plasmons allow for the guiding and directing of light into metallic circuits on the nanoscale, enabling photonic chips where similar to how electronic chips carry and guide electrons around in wires in electrical currents, instead light/photons are guided around for on-chip optical applications and experiments. 2D materials are a promising candidate for a future platform of on-chip light sources for PICs. But their 2D nature make their overall light emission efficiency low, and thus special care is required for how to best use them for practical applications.
Why
How to integrate 2D materials best and most efficiently with integrated photonics is currently a topic of much study. There have already been several studies observing laser-like emission from 2D materials coupled to integrated photonic cavities, as well as demonstrations of how general light emission efficiency of 2D materials can be enhanced by photonic nanostructures. However, there are currently very few studies into how to couple the emitted light from 2D material light sources into photonic waveguides with high efficiency. Because of their flat nature, 2D materials generally emit light from a large wide area, which poses a unique challenge in terms of collecting the light and squeezing/funnelling it into a nanoscale waveguide structure without a large amount of loss.
How
During the project I will be designing and fabricating several plasmonic waveguide geometries and integrating them with 2D materials in order to study the most efficient waveguide designs for collecting light emitted from the 2D material. The waveguides will utilise tapered geometries, accommodating a large area input of light, while still narrowing the waveguide cross-section down to just a few nanometres - essentially working as a funnel that squeezes light. By stacking different 2D materials into various heterostructures it is possible to make 2D light emitting diodes (LEDs). A big part of the project will be to develop such 2D LEDs and bringing them into contact with the optical chips and funnel their light emission into the waveguide system.
SSR
Integrated photonics is right now making the transition from purely academic research to large-scale commercialisation. Integrated photonic devices have a large variety of applications in future medical diagnostics and promises lower power consumption and faster switching and communication speeds for telecom applications, offering huge potential energy savings for the future communications industry. However, a major bottleneck to large-scale production of PICs is the integration of the photonic circuitry with the outside world. This can be solved by using on-chip light sources and detectors on the devices, but the materials used for making these components cannot always be freely integrated with the various materials and processes used in the photonic chip industry, requiring expensive custom solutions for different chip platforms. 2D materials are however extremely compatible with almost any substrates and are for this reason of key interest to be studied in their integration with photonic chips, as no matter which integrated photonics platform is needed for an application, 2D materials could almost always be used as on-chip detectors and light sources.