High-resolution polarization spectroscopy in the 10 μ region

A report is given of the experimental results obtained using a CO₂-laser saturation spectrometer with an external absorption cell, mounted between two polarizers, the saturating and probing beams having different polarizations. The molecules SF₆, NH₃, CF₂Cl₂, and BCl₃ were investigated and the nonlinear resonance corresponding to transitions with Δ J=0,±1 was observed.