Abstract

We report on the use of ultrashort light pulses from an injection laser for extremely accurate level splitting measurements in atoms. Use of optical pulse train interference spectroscopy (OPTIS)^1,2 allows resolution of the well-known hyperfine splittings of the Rb and Cs ground state comparable with the best rf experiments published so far. We can observe resonance widths for 10-GHz splitting frequencies down to 50 Hz and measure small frequency shifts which are due to buffer gases. These results are obtained with a pure optical excitation and detection scheme.

© 1986 Optical Society of America