Theoretical And Experimental Study Of Nd: Glass Rod Lasers In The Heat Capacity Operation

Solid state heat capacity laser(SSHCL) is a new generation of high power solid state laser, and it develops rapidly in recent years. It uses a new way of thermal management, by which laser operation is broken into two discrete and sequential operating steps, lasing step and cooling step, and therefore bottleneck of thermal effect in conventional steady state is broken through. This new way of thermal management and new thermal effect have attracted much interest. The major new work in this paper can be summarized as follows:1. The properties of Nd: glass rod lasers in the heat capacity mode, including the temperature and stress distributions, are simulated and compared with the conventional pumping and cooling scheme. It is shown that the heat capacity based lasers have the noticeable advantage over conventional lasers if very high output energy within a short time is required.2. A simulation model of flash lamp-pumped heat capacity Nd:glass rod lasers is presented. Based on this model, the temperature and stress distribution and the influence of the structure of the cavity on pumping uniformity of the rod are studied, the conditions of uniform pumping are given. It is shown that the Nd doping concentration and initial temperature affect the stress distribution of heat capacity lasers. The result is useful for the design, safe running, and cost-reduction of heat capacity lasers.3. A simulation model of oscillator in the heat capacity mode is presented. Based on this model, the influence of thermal effect on gain and optical aberration ofrod is studied. By using FFT method, the influence of thermal effect on wave distribution in the cavity and in the far-field, including intensity and phase distribution is studied, and compared with the experimental results. The result is useful for the improvement of beam quality and optimization of heat capacity Nd:glass rod laser.4. A prototype of heat capacity Nd:glass rod laser is designed, and preliminary experiments have been carried out. The experimental results of average power of 2W, lasing time of 15s, repetition rate of lOHz and a total laser energy of 30J in the heat capacity mode are obtained for the first time in our country. The experimental results show that Nd:glass rod laser is able to increase the repetition rate noticeably within a short time, at the same time good beam quality is maintained.