Implementation of a multi-functional femtosecond laser and diagnostic system for materials processing research

The development of femtosecond lasers with high repetition rates combined with high average power is making this technology more relevant to the needs of the manufacturing community particularly in the field of micromachining. Although the scientific community has extensively studied the interaction of femtosecond laser pulses with materials, there remain aspects of the machining process that merit further study, particularly in relation to hybrid and assisted laser processes. This paper reviews the implementation of a multi-functional femtosecond laser and diagnostic system designed to allow a comprehensive analysis of ultrafast machining processes. The laser system is based on a diode-pumped Ytterbium laser with a sub 500 fs pulse width at 1030 nm, 515 nm, and 343 nm with repetition rates up to 300 kHz. Shorter pulse durations (sub 100 fs) at these wavelengths are achieved using spectral broadening in a Photonic Crystal Fiber and subsequent pulse compression. Oscillator laser output at 29 MHz is also available. The process diagnostic system includes online Raman spectroscopy, Schlieren imaging, and high speed video analysis.