Summary form only given, as follows. This paper presents a lens-integrated terahertz imaging detector implemented in a 65 nm bulk CMOS process technology. The back-side illumination through a silicon lens increases the imaging SNR by 7–15 dB. The broadband detector design has been verified from 0.6 to 1 THz. At 1 THz the circuit achieves a noise equivalent power (NEP) of 66 pW/sqrt(Hz) and a responsivity (Rv) of 800 V/W for back-side illumination. The first 1 THz CMOS active imaging results with a lens are presented.