A magnetically polarized He-Ne laser

The performance of an internal mirror He-Ne laser that has a fraction of its capillary immersed in a strong transverse magnetic field will be described. The field is produced by permanent magnets which are built into the laser's housing. The laser produces a light output which has less than 0.1% of its power in the modes polarized orthogonal to the magnetic field. The attainment of such a high degree of polarization requires that the magnetic field be oriented relative to naturally occuring anisotropies of the laser cavity. Misalignment not only lowers the degree of polarization, but also decreases the laser's output.