Browsing by Subject "Burst mode"
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Item Open Access 3.5-GHz Intra-Burst Repetition Rate Ultrafast Yb-Doped Fiber Laser(Elsevier, 2016) Kerse, C.; Kalaycioʇlu, H.; Elahi, P.; Akçaalan, Ö.; Ilday, F. Ö.We report on an all-fiber Yb laser amplifier system with an intra-burst repetition rate of 3.5 GHz. The system is able to produce minimum of 15-ns long bursts containing approximately 50 pulses with a total energy of 215μJ at a burst repetition rate of 1 kHz. The individual pulses are compressed down to the subpicosecond level. The seed signal from a 108 MHz fiber oscillator is converted to approximately 3.5 GHz by a multiplier consisting of six cascaded 50/50 couplers, and then amplified in ten stages. The highly cascaded amplification suppresses amplified spontaneous emission at low repetition rates. Nonlinear interactions between overlapping pulses within a burst is also discussed.Item Open Access All-fiber burst mode laser system integrated with OCT for cataract surgery(IEEE, 2016) Kesim, D. K.; Kalaycıoğlu, Hamit; Kerse, C.; İlday, Fatih ÖmerWe demonstrate a burst-mode Yb all-fiber femtosecond laser system integrated with OCT for cataract surgery and aim to enhance further the procedure with lower collateral tissue damage, cleaner, efficient cuts with compact and robust structure.Item Open Access All-fiber laser systems that can operate in burst mode(OSA, 2016) Kesim, Denizhan Koray; Kalaycıoğlu, Hamit; Akçaalan, Önder; İlday, Fatih ÖmerFiber lasers which operate in burst-mode where densely spaced pulses occur inside bursts repeated at much lower repetition rates can be valuable tool for sensing and imaging. We introduce such lasers and propose possible applications.Item Open Access High-repetition-rate ultrafast fiber lasers for material processing(Institute of Electrical and Electronics Engineers, 2018) Kalaycıoğlu, H.; Elahi, P.; Akçaalan, Ö.; İlday, Fatih ÖmerUltrafast 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-μm wavelength range due to the relative maturity of the laser technology, we also report the development of Tm-fiber lasers around the 2-μm region specifically for tissue processing and laser-surgery applications.Item Open Access High-speed, thermal damage-free ablation of brain tissue with femtosecond pulse bursts(IEEE, 2016) Kerse, Can; Yavaş, Seydi; Kalaycıoğlu, Hamit; Asik M.D.; Akçaalan, Önder; İlday, F. ÖmerWe report a novel ultrafast burst mode fiber laser system and results on ablation of rat brain tissue at rates approaching an order of magnitude improvement over previous reports, with no discernible thermal damage. © 2015 IEEE.Item Open Access Tailoring nonlinear temperature profile in laser-material processing(2019-03) Kesim, Denizhan KorayAblation cooled material removal opened up great opportunities for understanding nonlinear processes. Especially using lasers as a tool to tailor nonlinear temperature gradient of material and engineering them to achieve effects such as high ablation efficiency, speed, and low collateral damage. Numerical simulations showed such engineering of the temperature gradient of material is possible for any repetition rate falling inside the ablation cooling regime. Two temperature model is used to investigate the effects of repetition rate, pulse energy, and burst duration. Simulations suggest ablation can continue indefinitely as burst duration increases. They also suggest there is an optimum pulse energy for any repetition rate in terms of efficiency of ablation regarding the material. The results of the simulations are confirmed by experiments using lasers with 1.6 GHz, 1.46 GHz, and 13 GHz repetition rate on biological and technical materials. The ablation threshold for a single pulse is lowered 100 times compared to our previous publication. Finally, related studies that can build upon the shown results are presented. A new thin-disk laser oscillator scheme is proposed that implements mode-locking regimes already established in fiber lasers. Dissipative soliton and similariton simulation results are promising for further studies. They can achieve high energy pulses with the help of nonlinear effects instead of limited by it. Then, a new computer generated hologram algorithm is explained where hundreds of layers can be generated from a single hologram. The algorithm utilizes diffusion as a tool to increase the degree of freedom which in turn decreases the cross-talk between layers.Item Open Access Ultrafast micromachining of Cu and Si at ultra-high repetition rates with pulse bursts(IEEE, 2016) Kerse, Can; Kalaycıoğlu, Hamit; Elahi, Parviz; Yavuz, Koray; Mirza I.; Bulgakova N.M.; İlday, F. ÖmerWe report a novel ultrafast burst mode fiber laser system, which can deliver pulses at ultra-high repetition rates in order to systematically investigate micromachining efficiency on copper and silicon samples. © 2015 IEEE.