High resolution graphene angle sensor based on ultra-narrowband optical perfect absorption

We propose and experimentally demonstrate high resolution angle sensors based on ultra-narrowband graphene perfect absorbers. Perfect absorption at wavelength of 1452.8 nm with absorption bandwidth of 0.8 nm is numerically demonstrated for a designed angle sensor based on single graphene absorber at normal incidence, and the angular width of the resonant absorption is only 0.05 degrees. In the experiment, peak absorption over 95% with bandwidth about 2.8 nm is measured at normal incidence for a fabricated graphene sensor, and the device has a wavelength-angle sensitivity over 17 nm per degree which agrees well with the simulation result. Meanwhile, an optoelectronic angle sensor with high resolution and fast response by using an array of graphene absorbers is proposed. The demonstrated graphene angle sensors with ultra compact size and high resolution could be of valuable applications in many fields. (C) 2021 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement