ELECTROOPTIC HIGH-RESOLUTION FABRY-PEROT SPECTROMETER

A single-crystal lithium niobate etalon suitable for high-spectral-res olution studies has been operated successfully. This etalon with a 5-c m clear diameter and a gap equivalent to 2 cm in air has been found to have very linear response in wave number as a function of voltage. Th e combined advantages of adjustment-free operation, linearity in opera tion, and high luminosity in a small size (as a result of the mu2 gain in the instrumental throughput caused by the large index of refractio n of the lithium niobate substrate) make for a rugged instrument that is ideal for long-term unattended field operation.