飞秒激光在大空气比微结构光纤中增强的非线性光谱展宽  

Enhanced Spectral Broadening by Femtosecond Pulses in Large-Air-Filling Fraction Microstructure Fiber

作　　者：胡明列[1] 王清月[1] 栗岩峰[1] 王专[1] 柴路[1] 邢歧荣[1] 

机构地区：[1]天津大学精仪学院超快激光研究室

出　　处：《中国激光》2004年第12期1429-1432,共4页Chinese Journal of Lasers

基　　金：国家973计划(编号:G1999075201和2003CB314904)国家自然科学基金(编号:60278003)国家863计划(编号:2003AA311010)资助项目。

摘　　要：报道了微结构光纤(MF)包层结构对超连续光谱产生影响的实验研究。在中心波长为820nm,脉冲宽度为35fs的激光脉冲作用下,在纤芯都为2μm,空气比分别为60％和80％的微结构光纤中获得不同的光谱展宽。由于空气比的增大,使得微结构光纤的有效模面积变得更小,其中传播的光场更能被局域在光纤纤芯中,非线性效应更加强烈,因此在空气比更大的微结构光纤中获得了更宽的超连续光谱。实验中分别在两种光纤中获得了近700nm(520-1200nm)和近1000nm(从350-1320nm)的超连续光谱,大空气比的微结构光纤中获得的非线性光谱展宽增强了1.25倍。对实验结果作了对比分析,并给出了相应的物理解释。The influence of the structure of microstructure fiber on the spectral broadening of femtosecond laser pulses is experimentally studied. These experiments demonstrate that the spectral broadening of 35-fs pulses of 820-nm Ti: sapphire laser radiation transmitted through 2-μm core diameter microstructure fibers can be enhanced by a factor of about 1. 25 by increasing the air-filling fraction of the fiber cladding from 60% up to 80%, and ultrabroad band continua which are almost 700 nm extending from 520 to 1200 nm and 1000 nm extending from 350 to 1320 nm are respectively generated from these two kinds of fibers. The comparison shows that the efficiency of the nonlinear spectral broadening process can be noticeably improved by increasing the air-filling fraction of the microstructure fiber cladding, due to a higher degree of light localization in the core of such a microstructure fiber.

关 键 词：激光技术 微结构光纤 飞秒脉冲激光 超连续光谱 

分 类 号：TN242[电子电信—物理电子学]