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Pushing ultrafast laser material processing into a new regime of plasma-controlled ablation

Periodic Reporting for period 2 - PULSAR (Pushing ultrafast laser material processing into a new regime of plasma-controlled ablation)

Reporting period: 2018-01-01 to 2019-06-30

Ultra-intense femtosecond laser pulses promise to become a fast, universal, predictable and green tool for material processing at micro and nanometric scale. The recent tremendous increase in commercially available femtosecond laser energy at high repetition rate opens a wealth of novel perspectives for mass production. But even at high energy, laser processing remains limited to high-speed scanning point by point removal of ultra-thin nanometric layers from the material surface. This is because the uncontrolled laser-generated free-electron plasma shields against light and prevents reaching extreme internal temperatures at very precise nanometric scale.
PULSAR aims at breaking this barrier and developing a radically different concept of laser material modification regime based on free-electron plasma control. PULSAR 's unconventional concept is to control plasma generation, confinement, excitation and stability. An ambitious experimental and numerical research program will push the frontiers of laser processing to unprecedented precision, speed and predictability. PULSAR key concept is highly generic and the results will initiate new research across laser and plasma material processing, plasma physics and ultrafast optics.
In the first period, PULSAR has developed a complete theoretical, numerical and experimental platform to characterize, understand and control nanometric plasmas generated in the bulk of transparent materials. The energy deposition process is crucial to understand the structuration of matter that follows after the laser pulse went through the medium. PULSAR team has built two complementary numerical codes to describe laser matter interaction when an ultrashort, femtosecond, pulse propagates inside a transparent medium such as glass and generates a plasma. In parallel, a novel experimental approach for plasma characterization has been built.
Meanwhile PULSAR team has also developed new means to confine laser-matter interaction and has successfully increased the ablation efficiency.
The platform PULSAR has built is now uniquely positioned to explore laser-matter interaction. This will enable the understanding of several long-standing problems in the field of ultrafast laser materials processing. The understanding of the fundamental phenomena at play is expected to be highly enabling to design novel strategies to process materials at high-speed, high efficiency and extreme spatial resolution.