Silicon-based asymmetric dimer-resonator grating for narrowband perfect absorption and sensing.

In this work, a method for designing an ultra-narrowband absorber platform is presented with asymmetric silicon-based dimer-resonators grating. Within the infrared range of 3000 ∼ 4000 nm, two narrowband absorption peaks with absorptivity greater than 99% are produced by the absorber. Moreover, during the optical sensing, such an absorber platform shows high-performance sensitivity factors for the absorption wavelengths at λ = 3468 nm (S = 3193 nm/RIU, FOM = 532) and at λ= 3562 nm (S = 3120 nm/RIU, FOM = 390).