Luminescence microscopy of single quantum dot pairs with nanometer spatial resolution

The possibility of determining the distance between two closely spaced blinking single colloidal quantum dots using super-resolution far-field luminescence microscopy is considered. Numerical simulation of microscope images of a single pair of point light emitters is performed for different modes of luminescence blinking observed in experiments with CdSe/ZnS core/shell quantum dots. The distance between the emitters is varied within the radiation wavelength $\lambda$, on the scale where effects associated with dipole-dipole interaction are typically manifested (from $\lambda/5$ to $\lambda/30$). An algorithm to determine the spatial arrangement of emitters in a pair with subdiffraction accuracy is developed and applied in model and laboratory experiments for different types of blinking dynamics of single quantum dots.