Frequency stabilization of an internal-mirror 1.523 /spl mu/m longitudinal Zeeman He-Ne laser

The polarization properties of an internal-mirror 1.523-/spl mu/m He-Ne laser under an axial magnetic field were investigated. When the magnetic field was around 12 mT, we could stabilize the laser frequency at either the center of gain profile or the symmetric two-mode position, and the stability achieved was better than 1 MHz.