A filter based on an unequal-arm Michelson interferometer is described that will attenuate a strong spectral line by a factor of 100 or more but transmit without reduction a weaker but more interesting line separated by a few hundred MHz from the strong line. The factors limiting the extinction ratio of the filter are considered and a practical instrument that gives results in good agreement with the theory is described.
© 1969 Optical Society of America
Equations on this page are rendered with MathJax. Learn more.