Pulsetrain 'burst' machining: ultrafast-laser microprocessing at ultrahigh (100 MHz) pulse-rates

摘要

Summary form only given. Successive generations of laser-materials processing have been differentiated by new ways of delivering fluence. Fluence delivered in intense ultrafast (lps) pulses has been very successful in capitalizing on nonlinear effects in absorption and ionization, and competing timescales of thermal transport vs. ablative cooling-it defines our newest paradigm. In this, transparent optical glasses and other wide-bandgap materials have become promising candidates for laser processing, despite their inherently weak linear absorption of light from most conventional laser sources. In this context, we developed the first direct comparison of laser-machining of fused silica by short-wavelength lasers and by ultrafast lasers-our notion of addressing the large bandgap via 'big photons' vs. 'many photons'.