Influence of spatial inversion-burnup inhomogeneities on the optimal position of the active medium in a laser for intracavity spectroscopy

Rate equations are used to investigate the influence of spatial inversion-burnup inhomogeneities in the active medium on the multimode lasing dynamics. It is shown that the active medium smooths the small-scale structure of the field energy distribution inside the active medium but does not influence the small-scale structure outside the medium. The relationship between the envelope of the small-scale structure of the field energy and the Fourier components of the profile of the dip in the lasing spectrum, caused by frequencyselective losses in the resonator, could be used to determine distortions found in the dip profile as compared with the selective loss profile. Requirements on the position of the active medium in a laser for intracavity laser spectroscopy are formulated as a function of the profile of the selective losses under study.