Plasmaron Coupling and Laser Emission in Ag-DopedCdSnP2

We report the observation of laser emission in optically excited CdSn${\mathrm{P}}_2$:Ag at a threshold of ∼50 ${\mathrm{k}\mathrm{W}/\mathrm{c}\mathrm{m}}^2$ at 20°K. From a study of the magnetic-field-induced shift in wavelength of the spontaneous and stimulated emission, the recombination mechanism is identified as band to band in a regime where electron-hybrid-plasmon (plasmaron) coupling is dominant. This is the first observation of plasmaron coupling in semiconductor laser action, and the first unambiguous experimental evidence for plasmaron coupling in semiconductors.