Fast Axial Gas Flow Research Articles

Gas laser for efficient sustaining a continuous optical discharge plasma in scientific and technological applications

A stable high-power laser is developed for the study and technical applications of a continuous optical discharge (COD). The laser based on the technology of a combined discharge in a scheme with a fast axial gas flow emits 2.2 kW at 10.6 μm per meter of the active medium in continuous and repetitively pulsed regimes with the electrooptical efficiency 20%. The sustaining of the COD plasma in argon and air is demonstrated at the atmospheric pressure. The emission properties of the COD plasma are studied and its possible applications are discussed.

A new helical coupling microwave antenna excited high-power CO/sub 2/ laser using a cylindrical resonant cavity

A new helical coupling antenna which was installed into a cylindrical microwave cavity (2.45 GHz) has been investigated to obtain high-power CO/sub 2/ laser operation. Laser experiments using a system of swirling fast axial gas flow parallel to the beam have been performed. The geometric properties of the helical antenna and the gas flow structures were optimized by using numerical codes analyzing the electric fields and gas flow dynamics. The swirling flow of the laser gas mixtures of CO/sub 2/-N/sub 2/-He=0.7-5-19 was caused in the discharge tube by an 8-slit nozzle. It is shown that the electric field obtained by the proper design of the helical coupling coil yields homogeneous discharges. The maximum output power and the efficiency (RF to laser power conversion ratio) was obtained as 1010 W and 15%, respectively, at a gas pressure of 45 torr and a gas flow rate of 57 kg/h.

High Power CO2 Laser Excited by TM010-Mode Microwave Discharge.

Microwave discharges for excitation of CO2 laser have been investigated. A resonant microwavecavity (2.45 GHz) has been employed to get high power laser operation. Laser experimentsusing a system composed of fast axial gas flow and axial electric field parrallel to the laserbeam have been performed. Both electric field distribution and resonant frequency of thecavity calculated by using the SUPERFISH were compared with the results of the measurements.Homogeneous discharges caused by the resonance of TM010 mode was obtained usingcylindrical cavity with reentrant type tuners on the both end plates. The laser output of 259 Wand the efficiency of 14% were obtained from a newly developed two-cavity CO2 laser module.