Observation of Goos-Hänchen shift in plasmon-induced transparency

We observed positive and negative Goos–Hanchen (GH) shifts in plasmon-induced transparency (PIT) in a metal–insulator–metal (MIM) multi-layer structure based on the attenuated total reflection response. Here, the MIM waveguide (WG) mode and the surface plasmon polariton (SPP) resonance act as low- and high-Q resonances, respectively. SPP also induced the transparency window in otherwise opaque wavenumber (k) regions. The observed GH shifts were caused by the relevant k-domain dispersion in PIT, which is controllable through the adjustment of the coupling strength between the MIM WG and SPP resonances. This effect, thus, can be recognized as a rigorous counterpart of slow light in electromagnetically induced transparency and other related phenomena in the frequency domain. The tunable GH shift in PIT in a MIM structure would enable applications in beam steering devices and high-sensitivity sensors.