(A) Theoretically calculated γr with a 1-nm dye–gold surface distance (7). The diameter of the nanoparticle is 20 nm. Perpendicular (red) and parallel (blue) dipole orientations are presented. (B) γabs based on the same configuration in A. Calculation based on another paper (6) (dashed lines) is added to confirm the theory in ref. 7 (solid lines). (C) Quantum yields, , based on A and B. Due to its magnitude, the quantum yield for the parallel dye orientation is multiplied by 100. (D) Measured emission spectrum of Alexa Fluor 532 dye molecules. (E) The factor that modulates the spatio-spectral profile in the spectral domain: . The factor, , is normalized to be 1.