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nm in place of 20 nm. Nevertheless, the difference between the two situations is not huge. Indeed, when the emitter is only 6 nm from the metal surface, the 20 nm rounded tip yields a stronger field enhancement in comparison to the flat one. These results stem essentially from the complex behavior of the electric field close to a metal tip $^{72}$. 

## III. CONCLUSION 

We investigated the performance of gold nanocones as optical antennas for enhancing molecular fluorescence. Compared to nanorods and nanospheroids, the great advantage of nanocones is that the spectral position of the LSPP can be tuned towards shorter wave- 

