Bojko O. Experimental investigations of intracavity saturated absorption resonances in He-Ne/I lasers pumped dy rf-dischatge.

The frequency stability of He-Ne/127I2 lasers pumped by transverse rf-discharge, the asymmetry of saturated-absorption resonances and the resonances of the fluorescence intensity of the intracavity absorbing gas have been investigated. The investigations carried out for the increasing frequency stability of He-Ne/127I2 lasers, the determination of the sources of the asymmetry of saturated-absorption resonances, the developing new methods of obtaining narrow resonances with high contrast in He-Ne/127I2 lasers and use them for laser frequency stabilization. It has been used the He-Ne lasers pumped by transverse rf-discharge with the intracavity absorbing iodine cells. The well-known third-harmonic technique has been used for registration of the resonances and for laser frequency stabilization. It have been shown that the frequency instability of such lasers is about six times as low as the instability of the lasers pumped by dc-discharge. It is achieved 5Ч10-13 for the integration time 100 s. The sources of the asymmetry of saturated-absorption resonances were determined as the joint action of the lenslike properties of the absorbing medium and the elastic velocity-changing collisions of absorbing molecules. It have been shown that the contrast of the resonances of the fluorescence intensity is about one order larger than contrast of the saturated-absorption resonances in the output power and that the lenslike properties of the absorbing medium don't affect their shape. Due to these properties the resonances of the fluorescence intensity are efficient references for the laser frequency standards. The results of the investigations can be used for raising metrological parameters of lasers, which are used for the practical realizations of the length unit.