Stimulated Raman emission in infrared excited gases

Using the pressure dependence of absorption, absorption coefficients and detunings were measured for CO2pump lines and the strong fat infrared emission in optically pumped D2O. The P (32) CO2line was found to be detuned ∼1.5 GHz from the ν2band transitions6_{6}, 6_{5} rightarrow 5_{5}, 5_{4}. The resulting emission lines at 50.3 μm and 66 μm were found to be detuned from their respective transitions by about the same amount. On the basis of these measurements and gain estimates for the far infrared, the resulting emission lines are identified as stimulated Raman emission.