Morales-Delgado Edgar E, Psaltis Demetri, Moser Christophe
Opt Express. 2015 Dec 14;23(25):32158-70. doi: 10.1364/OE.23.032158.
In this work we demonstrate 3D imaging using two-photon excitation through a 20 cm long multimode optical fiber (MMF) of 350 µm diameter. The imaging principle is similar to single photon fluorescence through a MMF, except that a focused femtosecond pulse is delivered and scanned over the sample. In our approach, focusing and scanning through the fiber is accomplished by digital phase conjugation using mode selection by time gating with an ultra-fast reference pulse. The excited two-photon emission is collected through the same fiber. We demonstrate depth sectioning by scanning the focused pulse in a 3D volume over a sample consisting of fluorescent beads suspended in a polymer. The achieved resolution is 1 µm laterally and 15 µm axially. Scanning is performed over an 80x80 µm field of view. To our knowledge, this is the first demonstration of high-resolution three-dimensional imaging using two-photon fluorescence through a multimode fiber.
在这项工作中，我们展示了使用双光子激发通过一根直径为350 µm、长度为20 cm的多模光纤（MMF）进行3D成像。成像原理与通过多模光纤的单光子荧光类似，不同之处在于传递并扫描聚焦飞秒脉冲到样品上。在我们的方法中，通过使用超快速参考脉冲进行时间选通来选择模式的数字相位共轭实现光纤内的聚焦和扫描。激发的双光子发射通过同一根光纤收集。我们通过在由悬浮于聚合物中的荧光珠组成的样品上的三维体积内扫描聚焦脉冲来展示深度切片。实现的横向分辨率为1 µm，轴向分辨率为15 µm。扫描在80×80 µm的视场内进行。据我们所知，这是首次展示通过多模光纤利用双光子荧光进行高分辨率三维成像。
