Larson Adam M, Yeh Alvin T
Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA.
Opt Express. 2008 Sep 15;16(19):14723-30. doi: 10.1364/oe.16.014723.
Broadband, sub-10-fs pulses, can be propagated through polarization-maintaining single mode fiber (PMF) for use in nonlinear optical microscopy (NLOM). We demonstrate delivery of near transform-limited, 1 nJ pulses from a Ti:Al(2)O(3) (75 MHz repetition rate) oscillator via PMF to the NLOM focal plane while maintaining 120 nm of bandwidth. Negative group delay dispersion (GDD) introduced to pre-compensate normal dispersion of the optical fiber and microscope optics ensured linear pulse propagation through the PMF. The minimized time-bandwidth product of the laser pulses at the NLOM focus allowed the nonlinear excitation of multiple fluorophores simultaneously without central wavelength tuning. Polarization sensitive NLOM imaging using second harmonic generation in collagen was demonstrated using PMF delivered pulses. Two-photon excited fluorescence spectra and second harmonic images taken with and without the fiber indicates that the fiber based system is capable of generating optical signals that are within a factor of two to three of our traditional NLOM.
宽带、亚10飞秒脉冲可通过保偏单模光纤（PMF）进行传输，用于非线性光学显微镜（NLOM）。我们展示了从钛宝石（Ti:Al₂O₃，重复频率75 MHz）振荡器通过保偏光纤向非线性光学显微镜焦平面传输近变换极限的1 nJ脉冲，同时保持120 nm的带宽。引入负群延迟色散（GDD）以预补偿光纤和显微镜光学器件的正常色散，确保了脉冲在保偏光纤中线性传播。非线性光学显微镜焦点处激光脉冲最小化的时间带宽积允许在不进行中心波长调谐的情况下同时对多个荧光团进行非线性激发。使用保偏光纤传输的脉冲展示了在胶原蛋白中利用二次谐波产生的偏振敏感非线性光学显微镜成像。有光纤和无光纤情况下拍摄的双光子激发荧光光谱和二次谐波图像表明，基于光纤的系统能够产生与我们传统非线性光学显微镜相差两到三倍的光信号。
