Ultrashort transients of variable duration have been generated at 10.6 &mgr;m by operating a fast optical switch with picosecond pulses from a mode‐locked Nd : glass laser. The switch, which takes advantage of the large free‐carrier contribution to the infrared optical susceptibility in Ge, has been used to generate megawattt picosecond pulses at 10.6 &mgr;m by synchronous operation of a TEA CO2laser with the 1.06 &mgr;m source.