INTRACAVITY SATURATION STARK SPECTROSCOPY

Our Stark cell (length 40 cm, spacing 2 mm, electrical fields up to 100 kv/cm) has been placed inside a $CO_{2}$ laser cavity (2 m gain tube, 4 m total length) using a ZnSe lens to create a waist inside the Stark cell. By comparison with our previous extracavity measurements, we obtain the same resolution (down to 300 kHz) the same accuracy (better than 100 kHz) a factor of 100 improvement in the sensitivity the saturation of all lines, including the normally forbidden ones Results on OCS and DCCCN will be discussed