用于水分子相干拉曼散射成像的光纤光源研究  

Fiber Laser for Coherent Raman Scattering Imaging of Liquid Water

作　　者：李典典 毕思敏 郝强[1] 季敏标[2] 杨康文 Li Diandian;Bi Simin;Hao Qiang;Ji Minbiao;Yang Kangwen(School of Optical Electrical and Computer Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;State Key Laboratory of Surface Physics,Department of Physics,Fudan University,Shanghai 200433,China)

机构地区：[1]上海理工大学光电信息与计算机工程学院,上海200093 [2]复旦大学物理学系表面物理国家重点实验室,上海200433

出　　处：《光学学报》2023年第23期341-345,共5页Acta Optica Sinica

基　　金：国家自然科学基金(11974248)。

摘　　要：水是生物体中含量最多的一种物质,了解生物体内水的分布对于理解水的生理功能来说至关重要。相干反斯托克斯拉曼散射(CARS)作为一种非侵入的成像技术,能够对生物体内的水分子进行实时且免标记的成像。因此,设计并搭建了用于水的CARS被动同步光纤激光器系统,该被动同步系统由掺铒和掺镱锁模光纤激光器构成,通过将主脉冲注入到从激光器腔内引入非对易相移,进而实现无源同步,同步失配距离达到347μm。结合功率放大技术、倍频技术和脉冲压缩技术,双路输出平均功率分别为146 mW和2 W,脉冲宽度分别为146.0 fs和9.1 ps。使用所搭建的同步光源在3156 cm^(-1)处对新鲜小鼠耳朵组织进行CARS成像,成像效果良好。该同步光纤光源有望推动CARS技术在快速、实时、高效病理学检测领域的应用。Objective Water provides an important chemical contribution to the function and degradation of biological systems,plays a central role in regulating cell volume,nutrient transport,waste removal,and thermal regulation,and serves as a medium for biological reactions.Coherent anti-Stokes Raman scattering(CARS)imaging,as an important tool in biomedical applications,has the advantages of chemical specificity,free of label,high sensitivity,and so on,and it is widely used in brain tumor analysis,disease pathology analysis,and pharmacokinetics.Therefore,it is of great significance to study the CARS imaging light source for water molecules.Methods Two synchronous mode-locked fiber lasers are constructed using the mode-locking scheme of a nonlinear amplifying loop mirror(NALM).A portion of the pulse output of the erbium-doped fiber laser is output by pulse amplification module and frequency doubling module,which is called pump light,while another portion of the pulse is injected into the ytterbium-doped fiber laser to achieve pulse synchronization.The output pulse of the injected ytterbium-doped fiber laser is then amplified and emitted as Stokes light.An appropriate central wavelength fiber Bragg grating(FBG)is selected to control the central wavelength of the output pulse in the ytterbium-doped fiber laser,ensuring that the frequency difference between the two lasers and the vibration frequency of water meet the resonance condition.Finally,a dichroic mirror(DM)is used to spatially combine the pump light and Stokes light.The synchronous two-color pulses are injected into a commercial microscope(Olympus,FV1200)for CARS imaging.Results and Discussions In the experiment,a master-slave injection passive synchronous two-color fiber light source is built,consisting of pump light and Stokes light.The central wavelengths of the two outputs are 783 nm[Fig.3(a)]and 1040.6 nm[Fig.2(c)],respectively.The pulse widths are 146.0 fs[Fig.3(a)]and 9.1 ps[Fig.2(d)],with an output power of 146 mW and 2 W,respectively.The relationship between

关 键 词：光纤激光器 被动同步 非线性光学 相干反斯托克斯拉曼散射 

分 类 号：O437[机械工程—光学工程]