Elahi Parviz, Kalaycioğlu Hamit, Akçaalan Önder, Şenel Çağri, Ömer Ilday F
Opt Lett. 2017 Oct 1;42(19):3808-3811. doi: 10.1364/OL.42.003808.
We report on the development of, to the best of our knowledge, the first ultrafast burst-mode laser system operating at a central wavelength of approximately 2 μm, where water absorption and, consequently, the absorption of most biological tissue is very high. The laser comprises a harmonically mode-locked 1-GHz oscillator, which, in turn, seeds a fiber amplifier chain. The amplifier produces 500 ns long bursts containing 500 pulses with 1 GHz intra-burst and 50 kHz inter-burst repetition rates, respectively, at an average power of 1 W, corresponding to 40 nJ pulse and 20 μJ burst energies, respectively. The entire system is built in an all-fiber architecture and implements dispersion management such that output pulses are delivered directly from a single-mode fiber with a duration of 340 fs without requiring any external compression. This gigahertz-repetition-rate system is intended for ablation-cooled laser material removal in the 2 μm wavelength region, which is interesting for laser surgery due to the exceptionally high tissue absorption at this wavelength.
据我们所知，我们报道了首个中心波长约为2μm的超快脉冲串模式激光系统的研制情况，在该波长下，水的吸收以及大多数生物组织的吸收都非常高。该激光器包括一个谐波锁模的1GHz振荡器，该振荡器又为光纤放大器链提供种子光。放大器产生500ns长的脉冲串，包含500个脉冲，脉冲串内重复频率为1GHz，脉冲串间重复频率为50kHz，平均功率为1W，对应的脉冲能量为40nJ，脉冲串能量为20μJ。整个系统采用全光纤结构并实现了色散管理，使得输出脉冲直接从单模光纤输出，脉宽为340fs，无需任何外部压缩。这种千兆赫兹重复频率系统旨在用于2μm波长区域的烧蚀冷却激光材料去除，由于该波长下组织吸收极高，这对于激光手术来说很有意义。
