Metamaterial absorber with the unexpected capability for harvesting electromagnetic energy has been regarded as a potential route for various applications, including chemical/biological sensing, cloaking and photovoltaic applications. In this study, we presented the simple absorber design made with Al/SiO2/Al sandwich structures through the involvement of hybrid dual-resonators that could allow the wideband light absorption covered from 450 nm to 600 nm with average absorptivity above 95%. Examinations of excited electric field, magnetic field and total magnitude of electric field in three-dimensional space at resonances were performed to clarify the origin of resonant behaviors. In addition, an equivalent inductance-capacitance circuit model was proposed that could qualitatively explore the geometry-dependent absorption characteristics by modulating the constitutive parameters of hybrid resonators. As a result, the designed light absorber might enable to be practically applied for various optical-management and photovoltaic applications, and even offered the tunability for other desired frequency regions.
Keywords: broadband absorption; light absorber; optical metamaterials; resonances.