Temporal Pulse Manipulation and Consequences for Ultrafast Laser Processing of Materials

Abstract

Following advances in ultrafast laser technology as a reliabletool for material probing and processing , we discuss various options forcontrol and optimization . The possibility to tailor the temporal shape ofultrashort laser pulses enables extended opportunities for material pro-cessing. The concept of optim izing laser interactions is based on thepossibility to regulate the energy delivery so that control of laser-inducedphenomena can be achieved and quality structures can be realized . Anexperimental demonstration of the possibility to design excitation se-quences tailored with respect to the material response is described, lay-ing the groundwork for adaptive optimization in materials structuring. Weshow that under particular irradiation conditions involving modulated ex-citation , the energy flow can be controlled and the material response canbe guided to improve processing results . This is particularly important forprocessing brittle materials. Further examples are given to illuminate thepossibility to optimize the kinetic properties of ions emitted from laser-irradiated semiconductors, using excitation sequences synchronizedwith the solid-to-liquid transformation time. Versatile sub-kilo-electron-volt ion beams are obtained, exploiting transitions to supercritical fluidstates with minimal energetic expenses. Temporally selective irradiationcan thus open up efficient thermodynamic paths, unfolding interestingperspectives for "intelligent," feedback-assisted processing of materials.