Development of a broadband and high-absorption graphene thermoelectric terahertz power meter

A high-absorption graphene-quartz sand composite coating was developed to enhance terahertz (THz) absorption over a broad frequency range. The coating demonstrated optimal absorption efficiency of 97.37% at 100 GHz when mixed in a 2.5:1 ratio of graphene to quartz sand, with a particle size of 350–550 μm. Absorption performance across the 100–220 GHz range was illustrated using a high-frequency absorption line graph. Two thermoelectric power meters were also developed with responsivities of 70.02 mV/W and 105.76 mV/W, respectively. Adjusting the graphene-to-quartz sand ratio allowed control over surface roughness, tailoring absorption properties for wide-band measurements. The composite coating’s absorption exceeds the 91–96% range of conventional THz absorbers, providing a promising solution for broad-spectrum THz applications and advancing THz power measurement technology.