Drilling speed optimization with wavelength and repetition rate for frequency tripled and doubled femtosecond laser pulses

Laser micromachining of metals under femtosecond regime is preferred for high process quality and deep hole drilling. It is very known that the choice of laser parameters is critical to improve the speed of production and to minimize the cost of operations. The development of reliable femtosecond laser sources with sufficiently short pulse duration, and average power is a one of key importance even if other parameters need to be optimized. We studied the influence of repetition rate and wavelength under short-pulse regime using second harmonic and third harmonic radiation of femtosecond lasers delivering pulses with 1 mJ energy at 1030 and 775 nm and variable repetition rate from 1 to 10 Khz. The wavelength study was motivated by the strong absorption dependence upon wavelength of our metal alloys as well as the repetition rate influence to the process speed.