Two-dimensional PtSe2 Theoretically Enhanced Goos-Hänchen Shift Sensitive Plasmonic Biosensors

Platinum diselenide (PtSe2), an emerging two-dimensional transition metal dichalcogenide, exhibits thickness-dependent refractive index, and hence, intriguing optical properties. Here, we employ it as a plasmonic sensing substrate to achieve significant enhancement in Goos-Hanchen shift sensitivity. Through systematic optimization of all parameters, four optimum sensing configurations have been achieved at different wavelengths ranging from visible to near-infrared region, where the Goos-Hanchen shift sensitivity receives four times enhancement in comparison with the conventional bare gold sensing substrate. There is a linear range of Goos-Hanchen shift with the tiny change of refractive index for each optimal configuration. The detection limit of the refractive index change can be as low as 5 × 10−7 RIU which is estimated to be lower by 2 orders of magnitude, and the corresponding sensitivity of biomolecules has a 1000-fold increment compared with that of bare gold-based sensors.