We have used an in‐cavity hot CO2cell to convert a conventional transversely excited atmospheric (TEA) CO2laser to operation on the 00 °2 sequence transitions. Careful cavity design enables us to attain efficient energy extraction. Output energies of 6 J per pulse have been obtained from a nonselective cavity, while a grating‐tuned cavity produces numerous sequence lines having output energies in excess of 2 J per pulse.