Polarization Properties and Frequency Stabilization of a 543-nm He-Ne Laser

The polarization properties of a commercial internal mirror type 543 nm He-Ne laser (Melles Griot 05-LGR-171) in a transverse magnetic filed and in zero m. f. have been studied experimentally. Main features in a zero magnetic filed are the simultaneous existence of an orthogonal and a parallel polarizations in adjacent axial modes and the sudden interchange of the mode polarization depending on cavity detuning (polarization flipping). In a characteristic magnetic filed where the Zeeman frequency equals the mode spacing, we found that the polarization flipping is suppressed and the polarization directions of the adjacent modes always become orthogonal by setting the angle between the directions of the filed and the polarization for around 30°-42°. Three methods of frequency stabilization exploiting cavity detuning dependence of the polarizations, the output power, and the beat frequency between axial mode spacings under the above conditions are presented, and one of them is demonstrated. A frequency stability of 2.1 x 10-8 (58 minutes) was obtained.