Instrument for high resolution spectral analysis with large optical throughput

摘要

A spectroscopic apparatus for the measurement of the spectral characteristics of weak light sources, for example laser Raman scattering from liquids, is formed of a tunable acousto-optical filter followed by a Fabry-Perot Etalon. Circuits are provided for tuning the two devices to the same light frequency or wavelength. The acousto-optical filter eliminates most of the light other than that of a particular wavelength while the etalon eliminates still more of the light other than that of the wavelength to which the device is tuned. The optical throughput of the two devices is so high that a very much greater proportion of the light of the particular wavelength from any source can be passed through the combination than through other devices of similar resolving power.