Properties of the PbSe diode laser

Diode laser action has been obtained at 8.5μ with PbSe. This laser is of potential interest for terrestrial communications since its emission is in the 8-to-14-μ atmospheric window, a spectral region of high atmospheric transparency where attenuation due to scattering by haze is low. Fabrication techniques are described which are based on controlling carrier type and concentration by adjusting the Pb:Se ratio. Below threshold for laser action, the emission exhibits two spectral peaks, one near 8.5μ which increases superlinearly with current and another near 10.1μ which increases slowly with current. Laser action associated with the 8.5μ peak is observed above a threshold Current density of 2000 A cm^-2. From measurements which did not resolve the cavity mode structure, the emission peak was found to shift to higher energies in a [100] oriented magnetic field at the rate of eV per gauss, or 17 Mc/s per gauss. This is the expected shift if the emission is associated with band-to-band transitions. The threshold current decreased to a fraction of its zero field value in a magnetic field of approximately 10 kilogauss, then increased slowly with higher fields.