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This paper report the experimental results of the effects of the inter-electrode distances and applied voltages for various operating pressure on the electrical characteristic of plasma discharge. We have studied the Current-voltage (I-V) characteristics and discharge currentgas pressure (I-P) for different inter-electrode gaps (3, 4, 5, 6, and 8) cm of the planar magnetron discharge. Also Paschen curve were measured at different spacing, The Paschen curves in Ar gas show that the breakdown voltage between two electrodes is a function of pd (The product of the pressure inside the chamber and distance between the electrodes). The results show the sensitivity of electrode separation lead to change the electrical characteristic of generating plasma; where The I-V characteristics of argon gas were deduced as a plasma system operated in abnormal glow discharge region, which is very impotent deposition sputtering. As well as the discharge current was increased for argon plasma discharge with the increasing of the working pressure lead to increase the deposition rate. Paschen curve is analyses at different working pressures and gap distances between two electrodes .the behavior between discharge current and discharge voltage for different gap distances between two electrodes was nonlinear, In addition the experimental finding validated that the suitable electrical characteristics of glow discharge current as a function to applied voltage for varying argon gas pressure at inter-electrode spacing equal to 5 cm.

The optical design process includes a myriad of tasks that the designer must be performed and consider in the process of optimizing the performance of the optical system. In this article, a design based on four groups of materials for a multilayer dielectric cold mirror: V2O5 \MgF2, Sic\MgF2, TiO2\MgF2, and Al As\MgF2 where MgF2 represents low refractive index and other material in each group represent high refractive index. A cold mirrors are a special dielectric mirrors that reflects the entire visible wavelength band, while the transmitting infrared wavelength band. These systems of mirrors are constructed for an event angle from 0° to 45° and are modeled with interference filters-like multi thin layer dielectric coatings. The results of our work designed shows the mirror based on Al As/MgF2 is the most promising design for cold mirror with the highest reflection in the visible region and the highest Transition in the IR region. In the spectrum range of 400-800 nanometers, the average transmission is much less than 1 %, while the average transmission is 95 percent in the wave band 800-2500 nanometer.

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