Multiple plasmon resonances of Au/Ag alloyed hollow nanoshells

We present a combination of experiments and theoretical simulations to investigate the optical response of Au/Ag alloyed hollow nanoshells. The results show that two distinct plasmon resonances corresponding to the dipolar and quadrupolar modes appear in the extinction spectra of nanoshells. As the thickness of the shell decreases the multiple modes consistently red shift and the resonant intensity increases. The results are validated by the calculated electric field distribution of nanoshells.