Opt Lett. 2020 Jun 1;45(11):3087-3090. doi: 10.1364/OL.45.003087.
Wide-field coherent anti-Stokes Raman scattering (CARS) microscopy offers an attractive means for the rapid and simultaneous acquisition of vibrationally resolved images across a large field of view. A major challenge in the implementation lies in how to achieve sufficiently strong excitation fields necessary to drive the third-order optical responses over the large focal region. Here, we report a new wide-field CARS microscope enabled by a total internal reflection excitation scheme using a femtosecond Ti:Sapphire oscillator to generate pump and broadband near-infrared Stokes pulses. The spectrally broad Stokes pulse, in combination with its inherent chirp, offers not only access to a wide range of Raman modes spanning ∼1000 to ∼3500 but also a straightforward means to select vibrational transitions within this range by simply varying the time delay between the pulses. The unique capabilities of this wide-field CARS microscope were validated by acquiring high-quality CARS images from the model and complex biological samples on conventional microscope coverslips.
宽场相干反斯托克斯拉曼散射（CARS）显微镜为快速、同时获取大视场范围内的振动分辨图像提供了一种有吸引力的手段。在实现过程中，主要的挑战在于如何获得足够强的激发场，以在大焦区驱动三阶光学响应。在这里，我们报告了一种新的宽场 CARS 显微镜，它采用全内反射激发方案，使用飞秒钛宝石振荡器产生泵浦和宽带近红外斯托克斯脉冲。光谱宽的斯托克斯脉冲，结合其固有的啁啾，不仅提供了对跨越约 1000 到约 3500 的大范围拉曼模式的访问，而且还通过简单地改变脉冲之间的延迟时间，提供了在该范围内选择振动跃迁的直接手段。通过从传统显微镜盖玻片上的模型和复杂生物样本中获取高质量的 CARS 图像，验证了这种宽场 CARS 显微镜的独特功能。
