Er:YAG laser ablation of tissue: Effect of pulse duration and tissue type on thermal damage

The thermal damage caused by 2.94‐μm Er:YAG laser ablation of skin, cornea, aorta, and bone was quantified. The zone of residual thermal damage produced by normal‐spiking‐mode pulses (pulse duration ≈ 200 μs) and Q‐switched pulses (pulse duration ≈ 90 ns) was compared. Normal‐spiking‐mode pulses typically leave 10–50 μm of collagen damage at the smooth wall of the incisions; however, at the highest fluences (≈ 80 J/cm²) tears were produced in cornea and aorta and as much as 100 μm of damaged collagen is found at the incision edge. Q‐switched pulses caused less thermal damage, typically 5–10 μm of damage in all tissues.