Integrated Design Of The Handred-joule Solid Laser And Analysis Of The Key Issues

Laser with high-energy and high-power plays a pivotal role in the study oflight and material interaction. Currently, in order to support the experiment relatedto the mechanism of UV damage, we focusing on creating a standard light source asthe “user device”. Which is the project we describes in this dissertation---the highbeam quality, high stability and high operating efficiency solid-state laser namedhundred-joule solid-state laser.The “user devece” has six components---Front-End System, Pre-amplifierSystem, Main Amplifier System, Frequency Conversion System, MeasurementSystem and Integrated Control System. This dissertation describes the experimenthow we optmize the design of hundred-joule solid-state laser: first determine theoutput indicators according to user’s request and the current condition of laboratory;secondly, optimize the laser machinism through reset the correspondingrequirements of various parts of the device. The project focus on designing asystematic energy flow distribution system function and rearrange the main systemof the device. This dissertation also present analysis and solutions of the key issuesoccur during the experiment such as issue related to the quanlity of laser beam andissue about operation safety.First of all, the dissertation shows how to set the requirement of correspondingparts depending on the optimal output points---100J/1ω/3ns and50J/3ω/3ns. At thebeginning part, the Front-End System uses an all-fiber structure with two amplifiedpoles. It also has a wavelength of1053nm and a function of pulse waveform reshape.The polarization of light can be controlled within10nJ. Throught the fiber-opticcollimator head the light injected into the Pre-Amplifier system which is our secondsystem. This system uses five thin neodymium glass rods to enhance the beam andthe output diameter can be enhancing to13mm. The Pre-Amplifier system also hasa space shaping function, with a no less than0.5mJ output energy. The outputbeam---pesent as an initial image plane---was put into the Main amplifier systemwhich is our third system. The Main amplifier system adopts a configuration offully thin neodymium glass rods amplifier. Through the Φ20, Φ40and Φ70threetwo-way amplifications and aΦ70one-way amplification boost, the beam diameterincrease to60mm and the energy of the beam enhance to100J. Next, the resultbeam goes into the Frequency Conversation System. This system adopts II+IIpolarization mismatch program which has two crystals driven by three motors. Inaddition, the efficiency of Frequency Conversation System is no less than50%and the final output is50J/3ω/3ns with a60mm’s beam-diameter. The last two systemsare Measurement System and Integrated Control System. One is designed tomeasure a near-field distribution, output laser energy and waveform of the1ω and3ω laser. The other is designed for collecting data from the beam measurement,controlling the key components of electricity, and triggering synchronization signalin each system.Secondly, the dissertation shows the designing of a systematic energy flowdistribution, shows the optical path arrangement of the Main Amplification Systemand the subsequent parts. According to the exist situation, after determining theindicator and considering the capacity of stable output in the Front-End System,first, we optimized the Pre-amplifier and the Main Amplifier Systems; then, wedetermined the systematic energy flow distribution; last, we designed the opticalpath arrangement, systematical image transmission and we distributed theamplificative, filterable and isolating units in a propure way. The systems (MainAmplifier System, Frequency Convension System, Measurement System andIntegrated Control System) placed on both sides of the truss.(7m L,1.5m W, and2.2m H) This structure reflected the compactness of the device.Finally, in the dissertation, I provide some analysis of the key issues such asthe beam quality and the operated safety of the device. Also, several appropriatesolutions are proposed. We could minimize the diffraction effect by larger the spacesoftening factor, limiting the fill factor and larger the munber of Fresnel number;We could improve the uniformity of near-field spot by adding spatial filters andLCLV (liquid crystal light valve) or by creating a cleaner environment; We couldimprove the safty of our device and keep it out of demage by controlling theB-integral, expanding the two-way off-axis structure and avoiding the ghost point.In order to achieve a higher stability of the device, we fixed the main body on thecarbon steel trusses which is built on stable foundation, adjusted the supporting partof the optical components to a stable state and lower the center point of the opticalpath.