Phase-driven progress in nanophotonic biosensing.

In the continuous pursuit of enhancing the sensitivity of nanophotonic biosensors by leveraging phase phenomena, a recent development involved the engineering of an atomically thin Ge₂Sb₂Te₅ layer on a silver nanofilm to generate large Goos-Hänchen-shifts associated with phase singularities. The resulting detection limit reached ~7 × 10^-7 RIU.