Laser ablation using a long-pulsed, high-fluence, CW single-mode fiber laser

Laser ablation is commonly used to produce microsized holes that are difficult to produce by conventional methods. To achieve non-thermal ablation, ultra-short-pulse lasers in the range of femtoseconds are often used. However, they are very expensive and their material removal rates are very limited due to the small amount of energy they can deposit and their low repetition rates. In this paper, the feasibility of using a continuous-wave fiber laser to perform thermal ablation via long-period pulses is investigated. The fiber laser has excellent beam quality and can be modulated to operate at different pulse widths in the range of tens of microseconds with high repetition rates. Results show that a pulse of 18 μs produces the optimum hole characteristics. Also, the removal rate is superior to other lasers used for laser ablation. A though-hole was generated in a piece of stainless steel 100 μm thick using only seven pulses.