Abstract

Ultrafast lasers provide two key aspects to laser materials processing that is difficult or impossible with conventional long pulse or CW laser sources. The short pulses allow for athermal material removal, immediately and directly vaporizing rather than melting the material to be removed. This athermal capability allows for material removal or patterning without recast material, splatter and redeposition, chipping, and a host of other detrimental side effects [1,2]. Ultrafast pulses also allow for the delivery of incredibly high peak power with reasonable and readily achievable pulse energy. For instance, the peak power of a typical 100uJ, 10ps laser pulse is on order of 10MW, while a 10ns pulse would have to be 100mJ to deliver the same peak power to the material. High peak power can be instrumental for initiating nonlinear absorption in materials that do not linearly absorb the laser wavelength, allowing a green or IR laser to function equivalently to a UV system, or even opening up new processing capabilities otherwise impossible such as processing inside bulk materials [3,4].

© 2015 IEEE