Mohsen Mehrabi

Optical absorbers have many applications in the field of optoelectronics, photovoltaics, and energy harvesting because of their capability to absorb electromagnetic waves, as well as their ability to adjust the absorption of specific wavelengths in the mid-IR region. In this study, a perfect optical absorber was designed, which included a gold reflective substrate, Al2O3 grating, a phosphorene layer, and air. By using the finite element method, the effects of irregularities on the geometry of the grating were investigated. Results show that, in the designed structure, irregular grating did not cause a significant change in the amount of absorption, and the absorption value for the phosphor layer remained at 99.9%. This perfect absorber also showed a stable wide range of absorption of up to 7.5 µm. Changing the incident light angle in the range of 0 to 50 degrees reduced the absorption in the phosphor layer by less than 10%.