Lens effect in the waveguide gas laser

Abstract

The radiation field of a planar waveguide laser with a nonuniformly heated gas causing the lens effect was studied. Conditions were found at which the losses at the walls and nonlinearity of the active medium (saturation) became essential. Calculations of the lasing of a xenon laser were performed with regard for the concurrence of modes. The radiation field distributions in the near and far diffraction zones were calculated. The results of calculations correlate qualitatively with experimental data.

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“…The asymmetry can be explained if mode competition can suppress one mode in a pair of two different mirror symmetric modes. Such a situation can occur, as was shown by the simplified mode competition model used in [1]. Figure 8 presents asymmetric versions of the fundamental mode (plots 1 and 2) and the symmetric second mode (plot 3).…”

“…The presence of a rather strong negative gas lens caused by the discharge of the laser can be considered as a factor in favor of an asymmetric radiation profile. To analyze this situation, the modes are calculated with the help of the following equation [1,2]:…”

“…The real part of δε (and hence the refractive index) depends on the transverse coordinate x due to the gas heating. The dependence of the refractive index on temperature was presented in [1,3] The temperature distribution between the electrodes was described by a parabolic function of x [3]. The imaginary part of δε describes the saturated gain by the radiation.…”

“…Recently it was demonstrated that the RF-excited waveguide Xe slab laser of medium gas pressure displays a number of uncommon properties [1,2]. A noticeable lens effect arises due to gas heating in the discharge.…”