Zhu Guanghao, van Howe James, Durst Michael, Zipfel Warren, Xu Chris
Opt Express. 2005 Mar 21;13(6):2153-9. doi: 10.1364/opex.13.002153.
We study and demonstrate the technique of simultaneous spatial and temporal focusing of femtosecond pulses, with the aim to improve the signal-to-background ratio in multiphoton imaging. This concept is realized by spatially separating spectral components of pulses into a "rainbow beam" and recombining these components only at the spatial focus of the objective lens. Thus, temporal pulse width becomes a function of distance, with the shortest pulse width confined to the spatial focus. We developed analytical expressions to describe this method and experimentally demonstrated the feasibility. The concept of simultaneous spatial and temporal focusing of femtosecond pulses has the great potential to significantly reduce the background excitation in multiphoton microscopy, which fundamentally limits the imaging depth in highly scattering biological specimens.
我们研究并演示了飞秒脉冲的同时空间和时间聚焦技术，目的是提高多光子成像中的信背比。该概念通过将脉冲的光谱成分在空间上分离成“彩虹光束”，并仅在物镜的空间焦点处重新组合这些成分来实现。因此，时间脉冲宽度成为距离的函数，最短脉冲宽度局限于空间焦点处。我们推导了描述该方法的解析表达式，并通过实验证明了其可行性。飞秒脉冲的同时空间和时间聚焦概念具有显著降低多光子显微镜中背景激发的巨大潜力，而背景激发从根本上限制了高散射生物样本中的成像深度。
