Two-frequency dye laser

A tunable two-frequency dye laser containing a single diffraction grating mounted at a grazing angle of incidence has been developed. By using a beam splitter mounted in the first diffraction order of the grating, it was possible to achieve lasing at two wavelengths in the common channel of the active medium. Contour maps of a spherical concave metal plate were obtained, the spacing between the contour bands being 10, 30, and 60 μm.