Investigation of narrow resonances in the saturation of the absorption of CO2 0001–0200 radiation in silicon tetrafluoride

An investigation was made of the saturation of the molecular absorption in the ν₃ band of silicon tetrafluoride SiF₄ by the CO₂ laser radiation corresponding to the 00⁰1–02⁰0 transition (λ = 9.4 μ). Measurements were made of the coefficients of unsaturated absorption of the P(30), P(32), P(34), and P(36) lines of the carbon dioxide laser radiation. Resonances were observed in the transmission of a weak opposite wave at the wavelengths of all four lines, and the positions of the resonances were determined relative to the central frequencies of the emission lines of the CO₂ laser. The parameters of the high-contrast resonances near the centers of the P(30) and P(36) lines were determined. Such resonances could be used to stabilize the emission frequency of the CO₂ laser. The measured values of the broadening constants were 4.1 ± 1.5 and 2.6 ± 2 MHz/mm Hg for the P(30) and P(36) lines, respectively. The minimum width of the observed resonances was 0.9 MHz at a pressure of 5.5 × 10^–2 mm Hg. It was concluded that SiF₄ could be used to achieve a high stability and reproducibility of the emission frequency of the CO₂ laser.