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 λ, on the scale where effects associated with dipole–dipole interaction are typically manifested (from λ/5 to λ/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.