High-Repetition-Rate Ultrafast Fiber Lasers for Material Processing

• Published in: IEEE journal of selected topics in quantum electronics 2018-05, Vol.24 (3), p.1-12
• Main Authors: Kalaycioglu, Hamit, Elahi, Parviz, Akcaalan, Onder, Ilday, Fatih Omer
• Format: Article
• Language: English
• Subjects: ablation-cooled laser-material removal; Ablative materials; burst mode; Fiber lasers; high repetition rate lasers; Laser ablation; Laser cooling; Laser modes; Lasers; lasers for material processing; M region; Materials processing; Physics; Power system stability; Pump lasers; Repetition; ultrafast fiber lasers; Ultrafast lasers
• ISSN: 1077-260X; 1558-4542
• DOI: 10.1109/JSTQE.2017.2771745

Ultrafast lasers operating at high repetition rates, in particular the GHz range, enable new possibilities in laser-material processing, particularly accessing the recently demonstrated ablation-cooled regime. We provide a unified perspective of the unique opportunities created by operating at high repetition rates together with our efforts into the development of enabling laser technology, including new results on further scaling up the capabilities of the laser systems. In order to access GHz repetition rates and microjoule-level pulse energies without requiring kilowatts of average power, we implement burst-mode operation. Our results can be grouped into two distinct directions: low- and high-power systems. Pulsed pumping is employed in the later stages of low-power systems, which have low burst repetition rates to achieve high pulse energies, whereas the technique of doping management is developed for the continuously pumped power amplifier stage of high power systems. While most of the developments have been at 1-\mum wavelength range due to the relative maturity of the laser technology, we also report the development of Tm-fiber lasers around the 2- \mum region specifically for tissue processing and laser-surgery applications.