A 500 MHz tunable CO2waveguide laser for optical pumping

A long-pulse CO
2
waveguide laser is described, which can be single frequency tuned over 500 MHz in about 80 lines. A peak power reaching 125 W at line center and 85 W at the tuning edge in the strongest lines makes the laser ideally suited for optically pumped FIR lasers. New FIR lines have been observed by pumping CH
3
OH in absorptions located up to 268 MHz from the CO
2
line center. FIR wavelengths have been measured, identified, and compared to calculations at a level of relative accuracy of
5 \cdot 10^{-5}
.