Enhanced ablation efficiency for silicon by femtosecond laser microprocessing with GHz bursts in MHz bursts(BiBurst)

Ultrashort laser pulses confine material processing to the laser-irradiated area by suppressing heat diffusion, resulting in precise ablation in diverse materials. However, challenges occur when high speed material removal and higher ablation efficiencies are required. Ultrafast burst mode laser ablation has been proposed as a successful method to overcome these limitations. Following this approach, we studied the influence of combining GHz bursts in MHz bursts, known as BiBurst mode, on ablation efficiency of silicon. BiBurst mode used in this study consists of multiple bursts happening at a repetition rate of 64 MHz, each of which contains multiple pulses with a repetition rate of 5 GHz. The obtained results show differences between BiBurst mode and conventional single pulse mode laser ablation, with a remarkable increase in ablation efficiency for the BiBurst mode, which under optimal conditions can ablate a volume 4.5 times larger than the single pulse mode ablation while delivering the same total energy in the process.

Automated summary

Ultrashort laser pulses can achieve precise material ablation by confining the processing area and suppressing heat diffusion. However, challenges arise when high speed material removal and higher ablation efficiencies are required. A study found that combining GHz bursts with MHz bursts in BiBurst mode significantly improves the ablation efficiency of silicon. Under optimal conditions, BiBurst mode can ablate a volume 4.5 times larger than single pulse mode ablation while delivering the same total energy.