Fig. 7
Normalized photoacoustic signal \((p/p({r}_{{\mathrm{d}}}=30{\,}{\mathrm{nm}}))\) as functions of radius. a Single nanosphere. b Suspension of nanospheres. For each cases, \((p/p({r}_{{\mathrm{d}}}=30{\,}{\mathrm{nm}}))\) is given for two configurations of of \(\frac{b}{a}=1.5\) and \(b-a=15\) nm. A 10-ns-wide Gaussian laser pulse is chosen for gold–silica nanosphere irradiation
