Pulsed single mode operation of distributed feedback quantum cascade l
asers is reported above room temperature at both 5.3 and 8 mu m wavele
ngths, Peak optical powers up to 60 mW at 300 K are obtained with a tu
ning range of similar to 60 nm from 100 to similar to 320 K. The linew
idth is limited by thermal drift during the pulse with a typical value
of 0.3 cm(-1) for a 10 ns long pulse at 300 K. (C) 1997 American Inst
itute of Physics.