Double heterostructure lead-salt lasers for high resolution gas spectroscopy

Lead-salt lasers have proved powerful tools in ir-gas spectroscopy. Their wavelengths can be selected in the 4–30-μm range by choosing proper compositions of the ternary compounds: PbS1− x Se x , Pb1− x Sn x Se, or Pb1− x Sn x Te. Fine tuning is achieved by temperature variation, application of a magnetic field, or hydrostatic pressure. The major handicap against their widespread use in gas spectroscopy is their relatively low operation temperature. Until recently cw operation has been achieved only below 77 K and pulsed operation not much above 100 K. Recently Groves et al. from the Lincoln Laboratory reported on PbTe-Pb1− x Sn x Te-PbTe DH lasers prepared by liquid phase epitaxy which could be cw operated at 77 K. Detailed results on PbS-PbS1− x Se x PbS as well as preliminary results on PbSe-Pb1− x Sn x Se-PbSe DH laser structures, which were prepared by the hot-wall evaporation—a modified molecular beam—technique, will be reported.</jats:p