Operation of a circularly polarized ring laser

Although there has been a large amount of experimental work published on the operation of the ring laser, nearly all of it was concerned with lasers operating in linearly polarized modes. In this paper the operation of a ring laser using the 1.153-μm wavelength transition of the He-Ne mixture in a cavity with no polarization constraint is reported. It was found that the two traveling waves operated in the same sense as circularly polarized modes and that there was no measurable coupling between the traveling waves via the amplifying medium, although there was still locking induced by coupling through cavity imperfections.