in particular the combination of the small beam divergence and the higher power allow one to illuminate an object of large size 1 m 2 or more with sufficient power that it will still produce enough scattered or transmitted thz light intensity to be detectable at very high rates above background radiation and thermal or other types of noise the present invention includes the detection of either the power or the electric field produced by reflected transmitted thz radiation or both measurements of the electric field can be used to enhance the sensitivity of detection such coherent detection is rendered possible by utilizing light pulses synchronously derived either from an accelerator from a drive laser an fel or synchrotron light as described in u s pat no 6 714 346 or using lock in amplifiers which synchronously integrate the detected pulses at the electron beam pulse frequency another method involves utilizing part of the emitted wavefront as a reference for the other utilizing the broadband nature of the thz illumination means that hyperspectral techniques can be utilized to provide bio medical chemical or morphological information about the object under investigation moreover phase sensitive detection can be utilized to uncover these features in three dimensions provided the material is not excessively absorptive or dispersive of the thz radiation it is clear that such a source can be extraordinarily versatile measurements of the power can be performed thermally using bolometric or pyrometric detectors or.