Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan.
Opt Lett. 2011 Mar 15;36(6):784-6. doi: 10.1364/OL.36.000784.
A significant advancement of cw lasing in Cr4+:Y3Al5O12 (Cr4+:YAG) double-clad crystal fiber grown by the codrawing laser-heated pedestal growth technique was demonstrated at RT. The optical-to-optical slope efficiency of 33.9% is the highest, to the best of our knowledge, among all Cr4+:YAG lasers, whether they are in bulk or fiber forms. The low-threshold lasing of 78.2 mW and high efficiency are in good agreement with the simulation. The keys to the high laser efficiency are twofold: one is the improved Cr4+ emission cross section and fluorescence lifetime due to release of the strain on the distorted Cr4+ tetrahedron, which also mitigates photobleaching in Cr4+:YAG; the other is the improved core uniformity at long fiber lengths. In addition, because of the low threshold, the impact of excited state absorption of the pump light is significantly reduced. The effects of crystal-orientation, self-selected, and pump-dependent linear polarization states were also addressed.
通过共拉激光加热基座生长技术生长的 Cr4+:Y3Al5O12（Cr4+:YAG）双包层晶体光纤中，cw 激光的显著进展在室温下得到了证明。在我们所知的所有 Cr4+:YAG 激光器中，无论是块状还是光纤形式，其光光斜率效率达到了 33.9%，这是最高的。78.2mW 的低阈值激射和高效率与模拟结果非常吻合。高激光效率的关键有两个：一是由于扭曲的 Cr4+四面体上的应变得到释放，Cr4+的发射截面和荧光寿命得到改善，从而减轻了 Cr4+:YAG 的光漂白；二是改善了长光纤长度下的芯部均匀性。此外，由于阈值较低，泵浦光的受激发射吸收的影响显著降低。还研究了晶体取向、自选择和泵浦依赖的线性偏振态的影响。
