Single fiber laser based wavelength tunable excitation for CRS spectroscopy.
Single fiber laser based wavelength tunable excitation for CRS spectroscopy.
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DOI：
10.1364/josab.30.001671
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发表时间：
2013-06-01
期刊：
影响因子：
--
通讯作者：
Hui R
中科院分区：
文献类型：
--
作者：
Su J;Xie R;Johnson CK;Hui R
我们展示了相干拉曼光谱（CRS）使用一个可调激发源基于单飞秒光纤激光器。在非线性光纤中，孤子自频移（SSFS）产生了泵浦脉冲与斯托克斯脉冲之间的频差。利用受激拉曼增益（SRG）和相干反斯托克斯拉曼散射（CARS）同时测量了环己烷C-H链的光谱，并进行了比较。我们演示了通过脉冲啁啾使用光谱聚焦来提高CRS光谱分辨率。我们分析了脉冲拉伸对CARS和SRG功率效率降低的影响。由于光纤系统中的色散，差分脉冲延迟是斯托克斯波长的函数。在进行需要扫描斯托克斯波长的光谱学时，必须考虑到这种差分延迟。我们收集了CARS和SRG信号，并将其作为啁啾脉冲与Stokes波长之间的时间延迟的函数在二维图中显示出来，并演示了如何从二维图中找到受激拉曼光谱。结合实际应用，讨论了系统优化的考虑策略。
We demonstrate coherent Raman spectroscopy (CRS) using a tunable excitation source based on a single femtosecond fiber laser. The frequency difference between the pump and the Stokes pulses was generated by soliton self-frequency shifting (SSFS) in a nonlinear optical fiber. Spectra of C-H stretches of cyclohexane were measured simultaneously by stimulated Raman gain (SRG) and coherent anti-Stokes Raman scattering (CARS) and compared. We demonstrate the use of spectral focusing through pulse chirping to improve CRS spectral resolution. We analyze the impact of pulse stretching on the reduction of power efficiency for CARS and SRG. Due to chromatic dispersion in the fiber-optic system, the differential pulse delay is a function of Stokes wavelength. This differential delay has to be accounted for when performing spectroscopy in which the Stokes wavelength needs to be scanned. CARS and SRG signals were collected and displayed in two dimensions as a function of both the time delay between chirped pulses and the Stokes wavelength, and we demonstrate how to find the stimulated Raman spectrum from the two-dimensional plots. Strategies of system optimization consideration are discussed in terms of practical applications.