Abstract
We processed metal and resin using intense femtosecond laser pulses transmitted through a hollow fiber. The laser pulses used in the experiment were generated by a regenerative amplifier and had a wavelength of 800 nm, a pulse duration of 50 fs, a pulse energy of 0.63 mJ (i. e., a peak power of 12.6 GW), and a repetition rate of 1 kHz. The hollow fiber was 1 m long, and its inner surface, coated with silver, was 0.7 mm in diameter. To avoid nonlinear modulation due to air breakdown, we evacuated the fiber's core. From by measuring the transmission characteristics of the fiber, we confirmed that optical pulses of 3.56 GW peak power (160 fs duration and 0.57 mJ energy) were obtained as fiber outputs when the fiber was straight. By scanning the output end of the fiber, we suitably processed a carbon tool steel and poly-ethylene terephthalate resin using fiber delivered femtosecond pulses.
