Atomic- and Nano-Layer Accelerated Femtosecond Ablation: A New Route to Laser Precision Manufacturing

About This Grant

Laser based micro- and nano-manufacturing is a key component for the resurgence of American manufacturing. To achieve this goal requires laser manufacturing to have higher processing speed and higher patterning resolution over large areas. A recently discovered phenomenon that has the potential to transform femtosecond laser manufacturing is explored in this research. By overlaying a dielectric substrate with a single atomic layer of graphene, MoS2, or hBN as a sensitizer, a femtosecond pulse can ablate sapphire, glass, or quartz 10-25 times faster. This project seeks to generate fundamental knowledge of this process, determine its applicability and limitations for laser manufacturing, and develop strategies to mitigate these limitations. The knowledge gained from this project will advance the understanding of light-matter interaction in the extreme limit where an atomic-thick hot dense plasma could play a vital role. This new process can have direct impacts on laser manufacturing in high-precision surface texturing with higher throughput. Combined with recent advances in transferring large-area atomic layer materials, this process can enable large scale super-resolution patterning on flat or curved substrates. This project also supports the future workforce in this emerging area of advanced manufacturing through student training. This project will address the following scientific questions: What is the mechanism for such a significant rate enhancement with only one atomic layer? Can this enhancement break the diffraction limit in far-field patterning? Is this process universal in that it can be applied to other atomic layer materials and beyond transparent dielectrics? Is this process self-terminating as the solid sensitizer vanishes and how can this be mitigated? Motivated by the necessity to address these unresolved scientific issues and the potentially transformative opportunities offered by this process, this project will execute a comprehensive study plan and generate transferable fundamental knowledge to advance this new field. Firstly, this project will investigate the interaction between substrate atoms and an atomic layer warm dense matter. This knowledge will enable controlling the ablation rate using the laser pulse width and the number of atomic layers. Secondly, this project will demonstrate ablated features with acceptable sidewall angles. Combined with atomic layer materials with sub-wavelength features, this knowledge will enable super-resolution patterning in the far field and in air. Thirdly, this project will extend this process to a wide range of substrates and sensitizers, enabling other researchers to adopt this new process. Lastly, this project will demonstrate that this process is self-terminating and could be mitigated by a flat-top-shaped laser beam and/or a renewable sensitizer based on nanolayer water. This knowledge will enable this process to ablate deeper holes, lines, and areas, which are building blocks for surface texturing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.