Arc discharge sliding over a conducting surface

Results of experimental and theoretical studies of the arc discharge which slides over the surface of a conductor are reported. Experiments were performed in air and argon ambients at various pressures. It is found that the velocity of the discharge plasma front depends linearly on the strength of the average electric field ahead of the front. A physical model of this phenomenon for the range of electric fields near the discharge threshold was developed. It is demonstrated that the mechanism related to thermal conductivity is responsible for the plasma front propagation

The physics and technology of CW RF-excited Ar-He-Xe laser with output power density of 0.5 W/cm2

Research interest in the Ar-Xe laser has been strengthened considerably because this laser now produces output powers at the level of Watts and is becoming the most promising light source in the wavelength region of a few microns. The lasing occurs on the IR transitions (1.73-3.51 ¿m) between the 5d-6d manifolds of atomic xenon. Our breakthrough in this type of laser came when our results obtained with the electron beam sustained technology showed the beneficial effect of operating at high gas densities. From these observations and the accompanying modeling, the idea was supported to consider the dissociative recombination of ArXe+ or Xe2 + molecular ions with electrons as the primary channel for filling the upper laser level. Apart from this recombination process by three body collisions the increased density leads to homogeneous line broadening which has also a favourable effect on the power and efficiency. However, a homogeneous inversion density requires a homogeneous discharge in a high-density gas. This is from a technical point of view a great challenge. For continuous operation the waveguide structure with RF excitation has shown so far the best prospects for maintaining a homogeneous discharge at high densities, say above 100 Torr. The RF discharges are characterized by thin positively charged layers (sheaths) near the electrodes. They play an important role in the stabilisation of the discharge. At increasing current density the discharge switches from ¿- to ¿-mod

The effect of the discharge frequency on the performance of RF excited CO2 waveguide lasers

Research interest in the Ar-Xe laser has been strengthened considerably because this laser now produces output powers at the level of Watts and is becoming the most promising light source in the wavelength region of a few microns. The lasing occurs on the IR transitions (1.73-3.51 ¿m) between the 5d-6d manifolds of atomic xenon. Our breakthrough in this type of laser came when our results obtained with the electron beam sustained technology showed the beneficial effect of operating at high gas densities. From these observations and the accompanying modeling, the idea was supported to consider the dissociative recombination of ArXe+ or Xe2 + molecular ions with electrons as the primary channel for filling the upper laser level. Apart from this recombination process by three body collisions the increased density leads to homogeneous line broadening which has also a favourable effect on the power and efficiency. However, a homogeneous inversion density requires a homogeneous discharge in a high-density gas. This is from a technical point of view a great challenge. For continuous operation the waveguide structure with RF excitation has shown so far the best prospects for maintaining a homogeneous discharge at high densities, say above 100 Torr. The RF discharges are characterized by thin positively charged layers (sheaths) near the electrodes. They play an important role in the stabilisation of the discharge. At increasing current density the discharge switches from ¿- to ¿-mod

State of and prospects for XeF(C-A) optically pumped lasers

Experimental and theoretical results are presented on an XeF(C−A) blue-green laser driven by 5-kJ energy. The laser was pumped by a ferrite-induced discharge of 90 cm in length. The output energy of 0.22 J was obtained with a plane-parallel resonator. A program to simulate laser operation has been developed. Numerical results for a wide range of conditions are compared with experiments performed by us and by other authors. It is found that intracavity refractive losses limit laser operation for XeF pressures above 3 torr. The laser efficiency strongly depends on the discharge-to-cavity length ratio. Possible ways to increase the laser power and efficiency are discussed