Grating transition radiation: A source of quasimonochromatic radiation

We have observed transition radiation at optical wavelengths, emitted by 3- 13-MeV electrons interacting with a diffraction grating. Near the direction df specular reflection we observed broadband radiation with the same prope rties as optical transition radiation from a flat surface. La addition, at large angles with respect to this direction and for low angles of incidence of the electrons on the grating surface, we observed the emission of quasi monochromatic radiation. This grating transition radiation may offer an alt ernative method for production of quasimonochromatic radiation in the: far- infrared to mm wavelength range. [S1063-651X(99)13211-2].