Intramode and Fermi relaxation in CO2, their influence on multiple-pass, short-pulse energy extraction

Analytical, experimental and numerical results concerning the influence of intramode and Fermi relaxation on multiple-pass, nanosecond-pulse energy extraction are presented. Multiple-pass energy extraction experiments show satisfactory agreement with the analytical and numerical calculations which predict a significant increase in extracted energy. In three passes, an amount of 9.7 J/l was extracted at an efficiency of 4.3%, These values are taken with respect to the volume of the beam inside the amplifier. In a single pass only 3.5 J/l was extracted.