Amplification in a mixture of isotopic CO2 molecules pumped by CO2 laser radiation

A theoretical analysis is made of the possibility of constructing a continuously tunable gas laser emitting radiation as a result of resonant optical pumping of a mixture of isotopic molecules by the radiation of a second laser. It is shown that a simple sealed laser can be built on this basis. The gain is calculated for binary and ternary mixtures of isotopic CO₂ molecules subjected to optical pumping with λ = 9.6 μ radiation emitted by a CO₂–N₂–He laser. It is shown that a gain of ~2X10^–3 cm^–1 should be obtained as a result of optical pumping of an isotopic mixture of CO₂ molecules at a pressure of 1 atm at 400° K and this should be true both under pulse and continuous emission conditions. In the pulse case, the pump energy density should be 10 J/cm². In the continuous case, the same gain can be obtained using waveguides resonators of ~100 μ diameter when the pump power is twice the threshold value of ~70 W.