Effects of beam intensity profile and optics on laser-sustained argon plasma

A laser-sustained argon plasma at atmospheric pressure was investigated numerically at low convection velocities. The plasma temperature distributions and power absorption were calculated for a laser power of 2 kW and for four different f number values 1.06-8.4. The results show that the plasma shape and power absorption strongly depend on the focusing geometry. Total absorption increases with f number from 55% to 83.2% of the laser power. On the other hand, the plasma shape and power absorption are not very sensitive to the intensity distribution of the laser beam and size of the focus spot.