Osaka University, Graduate School of Engineering Science, 1-3 Machikaneyama, Toyonaka-shi, Osaka 560-8531, Japan.
J Biomed Opt. 2013 Sep;18(9):096009. doi: 10.1117/1.JBO.18.9.096009.
We develop a coherent anti-Stokes Raman scattering (CARS) microscopy system equipped with a tunable picosecond laser for high-speed wavelength scanning. An acousto-optic tunable filter (AOTF) is integrated in the laser cavity to enable wavelength scanning by varying the radio frequency waves applied to the AOTF crystal. An end mirror attached on a piezoelectric actuator and a pair of parallel plates driven by galvanometer motors are also introduced into the cavity to compensate for changes in the cavity length during wavelength scanning to allow synchronization with another picosecond laser. We demonstrate fast spectral imaging of 3T3-L1 adipocytes every 5 cm-1 in the Raman spectral region around 2850 cm-1 with an image acquisition time of 120 ms. We also demonstrate fast switching of Raman shifts between 2100 and 2850 cm-1, corresponding to CD2 symmetric stretching and CH2 symmetric stretching vibrations, respectively. The fast-switching CARS images reveal different locations of recrystallized deuterated and nondeuterated stearic acid.
我们开发了一种相干反斯托克斯拉曼散射（CARS）显微镜系统，该系统配备了可调谐皮秒激光器，可实现高速波长扫描。声光可调谐滤波器（AOTF）集成在激光腔内，通过改变施加在 AOTF 晶体上的射频波来实现波长扫描。一个附在压电执行器上的端镜和一对由振镜电机驱动的平行板也被引入到腔中，以补偿在波长扫描过程中腔长的变化，从而允许与另一台皮秒激光器同步。我们在拉曼光谱区域约 2850cm-1 处每 5 cm-1 对 3T3-L1 脂肪细胞进行快速光谱成像，采集时间为 120 ms。我们还演示了在分别对应于 CD2 对称伸缩和 CH2 对称伸缩振动的 2100 和 2850 cm-1 之间的拉曼位移的快速切换。快速切换的 CARS 图像揭示了重结晶氘代和非氘代硬脂酸的不同位置。
