Modulation of single-band to multi-band based on tunable metamaterial absorber in terahertz range

Abstract

In this paper, a tunable metamaterial absorber with an absorption peak (94% amplitude at resonance frequency 11 THz) is proposed and measured at room temperature. This absorption peak is result by the bright-bright modes coupling effect on the cross shape metal particles array. The absorption peak is adjusted by changing the structural parameters P or b in experiments. It is found that this original absorption peak is not sensitive to the measured temperature. When the measured temperature is increased from 300 k to 390 k, the amplitude and resonance frequency of this absorption peak are basically retained. On the other hand, two newly resonance modes between the top and bottom metal layers are excited, which lead to two newly absorption peaks (65% amplitude at resonance frequency 21.9 THz, and 57% amplitude at resonance frequency 32.7 THz). Moreover, both newly absorption peaks can be controlled by changing the measured temperature. This tunable metamaterial absorber can both retain the original absorption properties and modulate two new absorption peaks.