Power Measurements At Submillimetre Wavelengths

Submillimetre-wavelength radiation is now used in a wide and growing range of research activities. Absolute power measurements are mainly required for the design and specification of components, and in the calibration of instruments used in emission spectrometry. Work at NPL on power meters for submillimetre lasers and similar sources is discussed, as are the problems of calibrating broad-band spectroradiometers used in stratospheric monitoring and plasma diagnostics.