Light can carry spin angular momentum (SAM) and orbital angular momentum (OAM). OAM, as a new degree of freedom, has played an important role in lots of fields and leads to promising applications. Understanding how the SAM and OAM interact and convert to each other can pave the road of OAM application. To understand the mechanism, I explored spin to orbital angular momentum conversion in:1. self-assembled concentric ring of gold nanoparticles and block co-polymer system, where the circularly polarized light is converted to light carry OAM by the plasmonic effect of Au. 2. the photonic crystal mimicking hexagonal structure system, where we try to understand the spin-orbit interaction from K space and real space point of view. 3. valleytronic system to see whether the involvement of OAM will change the selection rule. 4. twisted waveguide nanowires generating OAM. These fundamental research projects will help with a better understanding about the new twist degree of freedom OAM in the nano-photonics system and will help pave the road of OAM applications.

Besides the optical wave, I also explored the acoustic wave in one of my projects by using interdigital transducer generated surface acoustic wave. Surface acoustic wave has similarity with respect to surface plasmonic polariton. And in this project, I explore how the surface acoustic wave can interact with matter and mediate the assembly of nanoparticles and polymer system. We found the surface acoustic wave can help form micro-sized structure and help with the formation of hierarchical structure. The research project reveals the potential power of using surface acoustic wave to control assembly and to explore the fundamental material science topics.