Giant optical absorption of a PtSe 2 -on-silicon waveguide in mid-infrared wavelengths.

Low-dimensional platinum diselenide (PtSe 2 ) is a promising candidate for high-performance optoelectronics in the short-wavelength mid-infrared band due to its high carrier mobility, excellent stability, and tunable bandgap. However, light usually interacts moderately with low-dimensional PtSe 2 , limiting the optoelectronic responses of PtSe 2 -based devices. Here we demonstrated a giant optical absorption of a PtSe 2 -on-silicon waveguide by integrating a ten-layer PtSe 2 film on an ultra-thin silicon waveguide. The weak mode confinement in the ultra-thin waveguide dramatically increases the waveguide mode overlap with the PtSe 2 film. Our experimental results show that the absorption coefficient of the PtSe 2 -on-silicon waveguide is in the range of 0.0648 dB μm -1 to 0.0704 dB μm -1 in a spectral region of 2200 nm to 2300 nm wavelengths. Furthermore, we also studied the optical absorption in an ultra-thin silicon microring resonator. Our study provides a promising approach to developing PtSe 2 -on-silicon hybrid optoelectronic integrated circuits.