Influence of diffraction and nonresonant absorption on ultrashort pulse formation in a CO2 amplifier

A numerical investigation was made of the splitting of an amplified pulse in a CO₂ amplifier with a long interaction length. An allowance for nonresonant absorption in the medium and for spreading of the beam due to diffraction led to an increase in the time interval between the first pulse and the repeat pulses which appear because of rotational relaxation.