The effect of laser-rod properties on the energy transfer efficiency of pumping cavities using helical flash lamps

Monte Carlo calculations of energy transfer efficiency are presented for a wide range of configurations typical of practical large ruby laser systems using helical flash lamps. Details of mathematical models used are given. It is shown that the efficiency of the pumping cavity is greatly reduced if the ruby surface is roughened to form a perfect diffuser. Removal of the core of the ruby to form an annular cylinder causes a significant loss of efficiency for smooth rubies only. Also, the efficiency increases significantly with increasing ruby length and diameter, but there is only a marginal improvement with increasing ruby absorption coefficient.