Far-field superresolution imaging with dual-dye-doped nanoparticles

We propose to achieve superresolution in far-field fluorescence imaging by use of silica nanoparticles codoped with Cy3 and Cy5 molecules at a controllable ratio. Owing to the short distances between the dye molecules confined in the nanoparticles, Förster resonant energy transfer can efficiently occur between the Cy3 and Cy5 molecules. Therefore, the Cy5 molecules can quench the fluorescence emission from the Cy3 molecules in the outer region of focal spot of the excitation beam when the excitation intensity is properly chosen, thereby enhancing the resolution of imaging.