Reconfigurable multi-band, graphene-based THz absorber: Circuit model approach

Abstract

Using dual bias for a single graphene layer a multi-layer THz absorber is proposed. An exclusive circuit representation is derived and a two-layer structure is investigated as a reconfigurable multi-narrow band absorber. In order to optimize bias values and layers thicknesses, an evolutionary algorithm is used. Cost function defined regarding device input impedance and bias values is optimized correspondingly. The device operates in two modes depends on bias conditions. The first mode peak absorptions are 4 THz and 5 THz while the second mode shifts maximum absorption to 6 THz, 7 THz, and 8 THz. The device is simulated via both circuit models and full-wave simulations. According to results, the Finite Element Method verifies the exploited circuit model with acceptable accuracy. Such a reconfigurable and tunable response is in great demand in optical engineering and has numerous applications in designing sensors, modulators, detectors and imaging systems.

Keywords

• THz
• Absorbers
• Graphene disks
• Multi-bias graphene pattern
• Reconfigurable absorber
• The circuit model