Spectrum Detector Inc.’s T.rad series broadband digital radiometers offer sensitivity in the far-IR and the 0.1- to 100-THz regions of the spectrum. The state-of-the-art, thin-film crystalline pyroelectric detector, digital electronics and lock-in amplifier software enable 50-nW measurement with 2-nW resolution. The radiometer probes are available with detector areas of 1.5, 5.0 and 9.0 mm in diameter. The detector and preamplifier are mounted in a metal housing that includes a thermal isolation enclosure that has an SM1 threaded front bezel that takes windows, optics and filters. The only parameters that users have to set are range, filter tau and batch size. The software includes strip chart, statistics, tuning and setup screens.