Detection of hidden gratings through multilayer nanostructures using light and sound

Stephen Edward, Hao Zhang, Irwan Setija +4

We report on the detection of diffraction gratings buried below a stack of tens of 18 nm thick $\mathrm{Si}{\mathrm{O}}_2$ and $\mathrm{S}{\mathrm{i}}_3{\mathrm{N}}_4$ layers and an optically opaque metal layer, u…