Hi all, When you look at the IR absorbance spectrum of dry air, there's a big peak at ~ 2400cm^-1 due to vibrational transitions in CO2. But CO2 lasers always operate in the region between 9um and 11um, which is about 1000cm^-1 by my math. What are the practical criteria that make the ~1000um vibrational peak better than the 2400um vibrational peak for lasing? Can anyone refer me to a reference on and/or introduction to the theory of the CO2 laser that would answer this question? Thanks in advance for helping me out with this beginner question.