  We investigate the properties of finite gold nanocones as optical antennas
for enhancing molecular fluorescence. We compute the modification of the
excitation rate, spontaneous emission rate, and quantum efficiency as a
function of the nanocone base and length, showing that the maximum field and
fluorescence enhancements do not occur for the same nanocone parameters. We
compare the results with those for nanorods and nanospheroids and find that
nanocones perform better.
