Submillimeter waves

The submillimeter spectrum is of great interest for physicists, as matter in its different states exhibits remarkable properties there. Although some experiments have been made in this field, for instance, to prove the identity of light and electromagnetic radiation, it has remained comparatively unexplored because of the peculiar difficulties which arise in the production of some amount of power per unit bandwidth in this range. Significant results in generation have been achieved in the last few years at wavelengths well below 1 mm using the old electron tube technics. Work following new lines of thought, performed in different laboratories, has recently shown new possibilities. A short survey is given of the needs, results, and new possibilities of generating submillimeter waves.