Efficient monochromator to isolate VUV light generated by four-wave mixing techniques.

The lateral chromatic aberration from a LiF lens, which is positioned off-axis with respect to the incident light beams, is used to isolate the VUV light generated by the four-wave mixing technique from the intense pump light. The transmittance of the monochromator at the VUV wavelength is limited by the transmittance of a single lens. The ratio of transmitted-to-incident pump energy is 3.3 x 10(-6). A single monochromator with two interchangeable lenses can be used for either tightly focused or collimated pump beams.