Device Optimization And Experimental Research Of A Direct Current-discharge Driven Continuous Wave Laser

HF/DF chemical lasers have the advantages of high average power,high beam quality,high energy conversion efficiency and high atmospheric transmittance,therefore have an irreplaceable dominant position in the field of high energy lasers.Direct Current(DC)discharge-driven HF/DF chemical lasers are widely used as laser light sources in many diagnostic and test applications due to their low gas temperature and consumption,and stable power-time curve.In this paper,the optimized DC discharge-driven continuous wave HF/ DF laser platform's output power reached 473.9W/421.7W after redesigning and test the power supply and the discharge electrode,and choosing the proper cavity mirrors.The optimized laser system is based on an existed platform in our lab which output about 200 W of DF laser band.For DC glow discharge-driven CW HF/DF lasers,the optimized laser system is the highest output power performance reported nationally and internationally.The operating conditions and output performance of the existed DC glow discharge-driven HF/DF chemical laser were fully tested and evaluated.Under the condition that the optical axis of the laser was adjusted to about 15 mm downstream of the exit plane of the nozzle array,and the transmittance of the output mirror was 20%,an output power of 205.8W of DF laser was obtained.The task of this dissertation is to solve the problems of low power output on the discharge tube of the original power supply and sealing problems of the discharge electrode.The power supply and discharge electrodes of the laser platform are redesign,optimized and improved to obtain higher output power of the laser.Through comparison and experimental screening verification,the design scheme of parallel connection of constant-current power supply is proposed.Six T150-HI power supplies are parallel connected as one power supply module,twelve power supply modules form a high-voltage constant-current power supply system,which powered twelve discharge tubes.The newly designed power supply system has high output power,and also enabling the possibility of choosing the number of paralleled power supplies,so that the output power can be adjusted.Aiming at the electromagnetic interference caused by the operation of high-capacity power supplies,different measures such as the isolation of the sensors of pressure-leading tube,the lines separation of strong current and weak current,the separation and shielding of the power switch control lines,were used to solve the interference problem,and the utilization of UPS(Un-interruptible Power Supply)to provide power to the measurement and control system separately reduced the electromagnetic interference of the measurement and control system.In condition of solving the issue of low sealing problem of the original laser discharge electrode,the structure of the discharge electrode was modified.The optimized designing and machining of the new structure of the electrode,through the use of cone-sphere lock structure to ensure the sealing of the electrode assembly connection,was achieved.The optimized discharge electrode's discharge efficiency is higher,with better ablation resistance,and the components are easily replaceable.Comparing the output power of the original and optimized electrodes,the output power of HF laser increased from 389 W to 473.9W after replacing the new electrode,which increased about 21.8%,proving that the optimization of the new electrode has a great influence on the laser output power performance.A series of experiments were conducted on the newly upgraded HF/DF laser platform to test the optimized laser platform's performance.The experiments of different radius of curvature(concave reflect mirrors),different optical axis positions and different gas mass flow of HF laser optimization were conducted,and the DF transmittance experiment with different transmittance of the output mirror was carried out.The HF laser output of 473.9W was obtained under the condition of the optical axis of the laser adjusted to 15 mm downstream of the exit plane of the nozzle array,and the transmittance of the output mirror was 10%,the radius of curvature of the reflection mirror was 10 m,and optimized mass flow of fuels.The DF laser output of 421.7W was obtained under the condition of the optical axis of the laser was 15 mm downstream of the exit plane of the nozzle array,and the transmittance of the output mirror was 5%,the radius of curvature of the reflect mirror was 10 m,and optimized mass flow of fuels.The output power of the optimized DC discharge-driven CW HF/DF laser is double to the original platform,which can be used as the laser light source of the upgraded strong light lens closed-cavity test platform,or as the laser light source of infrared laser-matter interaction,and to carry out research on detector calibration,material effects etc.The optimized DC discharge-driven CW HF/DF laser platform has much broader application prospects than the original.