▎ 摘　　要

Graphene is an attractive material for terahertz (THz) detectors due to its unique properties of extremely weak electron-phonon interaction and small electronic heat capacity. In this paper, we demonstrate a lens-antennacoupled THz detector based on a diffusive superconductor-graphene-superconductor (SGS) junction, which has a sharp resistive transition at 1.4 K due to the proximity Josephson coupling. The SGS Josephson detector, measured with a dc superconducting quantum interference device (SQUID) readout, exhibits an electrical noise equivalent power (NEP) as low as 5 x 10-17 W/Hz0.5 at 0.1 K, which is still limited by the readout noise. Furthermore, the optical performance of the SGS Josephson detector is measured with a cryogenic blackbody radiation source, giving an optical NEP of 2.5-5 x 10-16 W/Hz0.5 at 1.4 THz in the temperature range from 0.1 K to 0.6 K.