Magnetic field tunable circularly polarized stimulated emission from midinfrared Ⅳ-Ⅵ vertical emitting lasers

摘要

Optically pumped laser emission from a midinfrared PbSe vertically emitting microcavity structure in a magnetic field applied in Faraday geometry is presented. It is shown that the emission line at a wavelength of about 7.9 μm splits into two circularly polarized components with opposite helicity. The splitting of the emission line in the magnetic field is caused by different refractive indices of the material inside the microcavity for left- and right-hand circularly polarized light, yielding two resonator modes. Thereby the emission wavelength can be fine tuned by, e.g., 2 cm~(-1) at 30 kG. At higher fields the laser emission is 100% circularly polarized. This indicates that lasing in this case originates from completely spin polarized carriers.