径向偏振、锁模光纤激光器研究

项目名称： 径向偏振、锁模光纤激光器研究

项目编号： No.61475166

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 李建郎

作者单位： 中国科学院上海光学精密机械研究所

项目金额： 82万元

中文摘要： 径向偏振光具有环形光强分布且其电场呈指向半径方向的轴对称分布。它具有紧聚焦等特性，在高分辨显微、光刻、粒子捕获及金属加工领域可获重要应用。自2006年首次实现连续输出的径向偏振光纤激光器以来，利用光纤激光器输出高效、高功率径向偏振光成为研究热点，但将锁模和径向偏振技术同时用于光纤激光器以产生超短径向偏振脉冲尚属研究空白。 本研究将首次把光纤激光器的径向偏振控制和锁模技术结合起来，利用光子晶体光栅作为偏振选择器，分别选择光诱导沉积石墨烯和半导体可饱和吸收镜（SESAM）作为锁模元件，搭建径向偏振锁模掺镱光纤激光器平台并开展实验研究，率先实现径向偏振锁模光纤激光器振荡，获得皮（飞）秒径向偏振脉冲输出。同时通过对激光器参量（光栅镜反射率、增益光纤长度和浓度、石墨烯或SESAM 调制深度等）的优化，理论和实验探讨增益光纤中偏振色散、自相位调制和模间耦合对对径向偏振锁模脉冲的影响。

中文关键词： 光纤激光器；径向偏振光束；被动锁模；超短脉冲；石墨烯

英文摘要： Characters)：Radially polarized light is knows for its annular intensity distribution and axissymmetrica electric field pointing to local radial direction.It is suitable for many important applications like in high-resolution microscopy and lithography, partical trapping and metal processing because of its unique features like sharp focusing and others. Direct emsssion of radially polarized light from a contineous-wave fiber laser has been attractive since the birth of first radially polarized fiber laser in 2006. Nevertheless, up to now, the investigation on the mode-locked and radially polarized fiber laser, which directly emits radially polarized and ultrashort pulse, still remained absent. In this investigation, we will, for the first time, associate the radial polarization control of fiberlaser with mode-locking technique. In our scheme, we will utilize a photonics crystal grating as intracavity polarization-selective component, and choose either an optically-driven-deposition graphene or a semiconductor saturable absorber mirror (SESAM) as the modelocker, and then build up an experimental platform of radially polarized,mode-locked and ytterbium-doped double-clad fiber laser for further investigation. This investigation would, for the first time, realize the oscillation of radially polarized and mode-locked fiber laser, and obtain ps or fs radially polarized pulse. Furthermore, by adjusting the laser parameters (including grating mirror's reflectivity, length and doping concentration of gain fiber, modulation depth of graphene or SESAM and etc), the effect of self phase modulation and mode coupling inside the gain fiber on the ultrashort and radially polarized pulse would be investigated both theorectically and experimentally.

英文关键词： Fiber laser;Radially polarized beam;Passive modelocking;Ultrashort pulse;Grepehene