Increasing femtosecond laser processing efficiency by hybridization with nanosecond laser

Abstract

The temporal coupling of femtosecond and nanosecond laser induces a remarkable increase in the processing efficiency 12 times more than that with an independent laser exposure. When femtosecond laser arrives before nanosecond laser, the dependence of the ablation efficiency on the time delay between the femtosecond and nanosecond laser pulses is very resemble to nanosecond laser traces. When femtosecond laser arrives after nanosecond laser, however, we observed an apparent delayed decaying component with a time constant of several hundreds of nanosecond in the ablation efficiency curve. Based on the current observation, we have explained the rather large enhancement in femtosecond laser ablation efficiency with synchronization between femtosecond and nanosecond laser in terms of silicon surface metallization due to the proceeding nanosecond laser. Such a progress in femtosecond laser micro processing makes it possible to maximize the processing speed and reduce the processing threshold energy. The current findings prominently reduce a various high order nonlinear effects which are frequently confronted when we focus high-power femtosecond laser pulses on the target under atmospheric conditions.