Abstract

In Doppler-free saturation spectroscopy the saturating beam ordinarily causes only a small fractional change in the transmitted probe intensity to avoid power broadening. We find, however, that if the probe is almost completely attenuated by the absorbing gas, the saturating beam can produce a large increase in probe transmission at the Doppler-free wavelength. The principle of the experiments is shown in Fig. 1. Strong transmission peaks on an essentially zero background allow direct noise-free detection.

© 1986 Optical Society of America