Hyper-Rayleigh and hyper-Raman scattering background of liquid water in two-photon excited fluorescence detection.
Hyper-Rayleigh and hyper-Raman scattering background of liquid water in two-photon excited fluorescence detection.
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DOI：
10.1021/ac961185o
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发表时间：
1997-04
影响因子：
7.4
通讯作者：
C. Xu;J. Shear;W. Webb
中科院分区：
文献类型：
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作者：
C. Xu;J. Shear;W. Webb
双光子激发荧光的检测实际上没有由线性散射引起的背景，因为双光子激发荧光发生在比激发光短得多的波长区域。这种特性可用于实现超灵敏的荧光检测。然而，与单光子激发荧光检测中的线性散射类似，出现了由非线性散射引起的背景是否可能限制双光子激发荧光的检测灵敏度的问题。在这项工作中，在一个标准的落射荧光几何双光子诱导的散射的液体水和双光子激发的染料荧光之间的定量比较表明，相对散射背景通常减少了数量级的双光子激发相比，单光子激发与共焦检测。在840 nm入射波长下，液态水的超瑞利和超拉曼（3400 cm-1）截面分别测量为8 × 10（-62）和7 × 10（-63）cm-4·s/光子，绝对值相对于荧光素的已知双光子荧光激发截面进行校准。
The detection of two-photon excited fluorescence is practically free from background caused by linear scattering because two-photon excited fluorescence occurs at a much shorter wavelength region than the excitation light. This property can be used to achieve ultrasensitive fluorescence detection. However, similar to linear scattering in the detection of one-photon excited fluorescence, the question arises whether background caused by non-linear scattering may limit the detection sensitivity of two-photon excited fluorescence. In this work, quantitative comparisons between two-photon induced scattering of liquid water and two-photon excited dye fluorescence in a standard epifluorescence geometry show that the relative scattering background is typically reduced by orders of magnitude in two-photon excitation as compared to single-photon excitation with confocal detection. Hyper-Rayleigh and hyper-Raman (3400 cm-1) cross sections of liquid water have been measured to be 8 x 10(-62) and 7 x 10(-63) cm4.s/photon, respectively, at 840 nm incident wavelength, with absolute values calibrated with respect to the known two-photon fluorescence excitation cross section of fluorescein.