در ليزر مولكولي نيتروژن با تحريك طولي GSFUR بررسي تشديدگر ناپايدار خودپالاينده تعميم يافته

Experimental Investigation of Generalized Self-Filtering Unstable Resonator in a Longitudinally Excited Molecular Nitrogen Laser

In this research work the application of the generalized self-filtering unstable resonator (GSFUR) in a longitudinally excited molecular nitrogen laser has been investigated and compared with the plane-parallel resonator. In a typical design of magnification M=-5, the beam divergence of 0.33mrad, and the brightness of 1.3*10w/cm2.Sr have been obtained. For a plane-parallel resonator of equivalent length these figures are -lmrad and 2.3x107w/cm2.Sr respectively, where it is shown that in the GSFUR design there is a reduction in the beam divergence by a factor of 3 and enhancement in measured brightness by a factor of 56, as compared with the plane-parallel design. Using a field limiting aperture as an output coupler, the beam profile in the far-field and near-field were Gaussian and donut shape, respectively. A mathematical model based on the rate equations for the gain medium and equation for the electric circuit is introduced and the results are consistent with the experimental measurements.