Plasmon Control of Quantum States in Semiconductor Nanocrystals

Summary

Thanks to the light-induced collective oscillations of free charges at the boundary between a conducting material and a dielectric, known as surface plasmon resonance, metallic nanostructures can exhibit strong light absorption and scattering. The sensitivity of these resonances to the local environment and shape of the metallic structures allows them to be used, for example, in chemical sensing and cancer therapy. Semiconductor and metal-oxide nanoparticles expand possible wavelengths of surface plasmon resonances into the infrared spectrum and can possibly allow for coupling of the surface plasmon resonances of the nanoparticle, which are of classical nature, to the particle’s semiconductor band structure, which arises from quantum states of the charge carriers. These charge carriers are the electron-hole pairs known as excitons in the semiconductor.

We have recently developed a new method to produce doped transparent-metal-oxide plasmonic nanocrystals and used these to demonstrate for the first time a plasmon-exciton coupling in any plasmonic semiconductor system. Our goal in this project is to further explore the plasmon-exciton coupling in semiconductor and metal-oxide nanostructures and to develop methods to use this coupling for plasmon control of the quantum states of single defects and for their entanglement. We expect this will open the door for these systems to be deployed in quantum sensing and computing applications. In particular, we believe our studies will lead to the design of inexpensive and highly sensitive magneto-optical sensors for thermal imaging and molecular sensing.