Abstract: A semiconductor laser produces infrared radiation suitable for jamming a heat seeking missile, wherein a wavelength of the radiation is in a range of 2-5 microns, and the laser has a semiconductor lasing medium of Pb1-xSexPb1-xSnxSe or Ga0.84In0.16As0.14Sb0.86. These materials can be doped to provide a p/n junction, wherein the laser is excitable by electric current passing through the p/n junction. The third one of these materials can be constructed also as a uniform undoped slab which is excitable optically. Cooling of the lasing medium is accomplished by use of a lithium heat sink thermally coupled to the lasing medium by a diamond thermal diffuser which conducts heat from the relatively small region of the laser to spread out the thermal energy along a relatively large surface of the heat sink. Modulation circuitry is connected to the excitation apparatus to provide a pulse train of the radiation.