Effects of laser mode structure on damage in quartz

Observations are reported of the differences in the damage properties of crystalline quartz for ruby laser pulses having different mode structures. The damage threshold values for the multimode laser are found to depend on the propagation and polarization directions of the incident laser pulse. The threshold values for the TEM00laser are independent of propagation and polarization directions. The damage patterns produced when either of the two lasers is focused within the sample show a distinct characteristic dependence on the laser propagation direction within the crystal. A phenomenological model is developed to explain the differences in the damaged properties produced by the two lasers.