We demonstrate a new optical power detector technology with spectral coverage from UV to far-IR; 325 nm to 25 µm. Recently we have extended the coverage to THz (yet unpublished). The minimum detectable power is in the order of nW. The dynamic range reaches 108.
For details, see the paper in Optics Letters (open access): J. Rossi et al. "Optical power detector with broad spectral coverage, high detectivity, and large dynamic range".