Abstract

In traditional absorption spectroscopy the change of light beams intensivities I is measured. As a rule the sensitivity and accuracy of measurements of value I/Io are not exceed 10^-3. The low sensitivity and accuracy of measurements of photometric values limit a progress in development of modern methods in absorption spectroscopy. On the other hand the achievements in measurements of phase and frequency of the light sources are considerable. For example. the accuracy in frequency measurements of He-Ne lasers approaches to 10^-14[1]. Take into account this. the transition from the measurements of photometric values to the measurements of the phase and frequency of the radiation in presence of its absorption is very interesting.

© 1996 IEEE