Investigation On Mecahanisms And Characteristics Of Strontium And Strontium Halide Vapor Laser

The strontium vapor laser excited by HRR(high repetition rate) pulsed discharge is an important hotspot in the laser area, which has many characteristics including multiple laser lines(covering waveband from blue to infrared),with different mechanisms, higher output power and efficiency and so on. These lasers can be widely used in material processing, microelectronic technology, laser medical treatment and infrared technology. Scientists constantly have great interest in working on the output performance and the mechanism of strontium vapor laser, and make a lot of impornant results, however, the micro-kineitc process, the laser mechanism and the characteristics of strontium and strontium halide vapor lasers are still to be deeply investigated. In the paper the pulsed strontium laser is systematically studied whatever on theory or experiment aiming at accomplishing the task of National Natural Science Foundation Program, and some important results are achieved during the research.In Chapter 1, the development history, the background and the research state of metal vapour lasers(MVLs) especially the strontium and strontium halide vapor lasers are compendiously introduced. The principle and the technology of strontium vapor laser with different transtion mechanisms including the self-terminating laser, the collisional recombination laser and the metastable-metastable laser are discussed and analyzed. Some suggestions to solve the subsistent problems of strontium vapor laser and the research purpose are given out. In Chapter 2, a self-consistent model is developed to simulate the kinetics of alternate oscillation of self-terminating and recombination lasers(1090/430.5nm) in univalent ions of strontium excited by HRR pulsed discharge. Temporal behaviors of level population densities,the electron density and the cavity photon density are obtained. The emission process of alternate oscillation of the two lasers above, the characteristic of the laser pulse and the population inversion mechanism are also analyzed and explained. It is considered whether the electron temperature can rise up quickly in the early discharge and fall down rapidly during the discharge afterglow is the key to realize the alternate oscillation of self-terminating and recombination lasers in univalent ions of stroantium in experiment. In Chapter 3, a small-scale cataphoresis He-Sr+(Ca+) recombination lasers are made. By means of the cataphoresis effect in HRR pulsed discharge, the axial uniform distribution of metal vapor density and the stable laser output are realized. The maximum laser output power of 819(136)mW and the specific power of 56(5.9)mW/cm3 are obtained for Sr+(Ca+) recombination lasers, respectively. Dependences of working parameters such as the pulsed frequency, the supply voltage and the helium pressure on laser output characteristics are measured and discussed. and a set of optimal work parameters is got. It provides a new way to make a practical device of this kind of laser. In Chaper 4, an investigation of a He-SrCl2 vapor laser excited by Blumlein discharge circuit is made. SrCl2 compound is successfully employed as a lasant in exploring the discharge excitation strontium vapour laser with a novel laser discharge tube, and the laser output at multiple lines(-1μm,-3μm and 6.45μm) in strontium vapor are realized. The problem of the intense chemical reaction between strontium vapor and discharge tube in the metallic strontium laser is effectively solved, which prolongs the lifetime of the laser. Total output power of multiline of 1.32W and the power specific of 12.46mW/cm3 are achieved, in which the component of the 6.45μm laser line accounts for 78.1%.The characteristics of laser and current pulses in a He-SrCl2 vapor laser are measured and analyzed,and the improtant experimental rules are got In Chapter 5, a sealed operation MVL with periodical refreshment of the buffer gas are designed and made. The spectral structures of 578nm and 511nm laser lines, produced by CuBr laser with lower Ne buffer gas pressure are measured and analyzed under different working temperature and exciting voltage. It is found that 578nm laser line is closely dependent on the work temperature and the exciting voltage, but 511nm laser lines not. In the same way the study on the spectral structure of 430.5nm strontium ion recombination laser is done, and it is shown that the line shape of 430.5nm laser is stable and monochromatic.