Seminar:

The interaction of light and matter includes an evanescent component that is tightly bound at the material interface. Near a sharp tip, these optical “near fields” can be concentrated to below the diffraction limit, thereby enabling optical microscopy with nano-scale resolution. The near-field interactions between a single emitter and the tip can also modify the local density of optical states, which can impart simultaneous control over the emission direction and polarization, and can be used to suppress the intensity variations resulting from quantum fluctuations (blinking). In this talk, I will discuss some recent work showing how metallic tips can modify the emission properties of semiconductor nanocrystal quantum dots. If there is sufficient time, I will also discuss the novel optical properties of gallium nitride nanowires, which exhibit light trapping and surface-specific fluorescence spectra. These nanowires are being investigated for solar- driven photo-electrochemical water splitting.