High efficiency GHz laser processing with long bursts

Bursts of GHz repetition rate pulses involve more ablation mechanisms than single femtosecond pulses. Efficient ablation by GHz laser pulses is a multi-step process, consisting of a first thermal incubation phase, followed by a highly efficient ablation phase. GHz ablation therefore combines thermal and non-thermal ablation mechanisms. With an optimal choice of the burst duration, the ablation efficiency can be highly enhanced. Long bursts, comprising tens of pulses to hundreds of pulses, are needed to take full advantage of the increase in ablation efficiency.