Infrared absorption suppressed terahertz metamaterial absorber

Current terahertz metamaterial absorber (TMA) is easily disturbed by infrared (IR) radiation background in real applications. We present a TMA design method with the ability of IR absorption suppression, which uses the slit pattern on the metal surface to control the absorption spectrum. Experimental results show that the designed and processed TMA produces an absorption peak of more than 80% at the resonant frequency of 1.33 THz and achieves less than 3% absorption in IR bands above 12 THz. The photothermal conversion noise caused by IR absorption at room temperature can be decreased by 20.9 times compared with a previous design. We believe it provides new paths in the TMA research and is helpful for the development of high-sensitivity THz microbolometer.