Broadband Silicon Absorber of Terahertz Radiation

A three-layer structure is fabricated on a low-resistance silicon substrate using plasma chemical etching. We study it experimentally and show that a substrate with such a structure can be used as an absorber of terahertz (THz) radiation in the frequency range of 0.5−2.0 THz. For this structure, absorbance in the indicated frequency range is measured to be more than 95%.