Nickel composite film for terahertz wave broadband absorption

Abstract

Due to the poor response of natural materials in the terahertz (THz) frequency band, ultra-broadband absorption of THz waves is a challenge. In this work, a nickel-composite film (NCF) is experimentally demonstrated for the ultra-broadband absorption of THz waves. The NCF consists of nickel foam, polydimethylsiloxane (PDMS), and few-layer graphene. The nickel foam has a three-dimensional structure that can be filled by the PDMS and few-layer graphene. By controlling the mass fraction of few-layer graphene in the PDMS, we can reduce the surface reflection of THz waves and achieve broadband absorption. For a 0.5-mm-thick NCF, when the mass fraction of doped few-layer graphene is 2%, the qualified bandwidth (with an absorption rate more than 90%) reaches 3.2 THz. More importantly, for different thicknesses of nickel foams, the absorption bandwidth can be enhanced by changing the mass fraction of few-layer graphene.