Bargo Paulo R, Prahl Scott A, Jacques Steven L
Oregon Medical Laser Center, Providence St. Vincent Hospital, 9205 S.W. Barnes Road, Portland, Oregon 97225, USA.
Appl Opt. 2003 Jun 1;42(16):3187-97. doi: 10.1364/ao.42.003187.
If a single optical fiber is used for both delivery and collection of light, two major factors affect the measurement of collected light: (1) the light transport in the medium that describes the amount of light that returns to the fiber and (2) the light coupling to the optical fiber that depends on the angular distribution of photons entering the fiber. We focus on the importance of the latter factor and describe how the efficiency of the coupling depends on the optical properties of the medium. For highly scattering tissues, the efficiency is well predicted by the numerical aperture (NA) of the fiber. For lower scattering, such as in soft tissues, photons arrive at the fiber from deeper depths, and the coupling efficiency could increase twofold to threefold above that predicted by the NA.
如果使用单根光纤进行光的传输和收集，有两个主要因素会影响收集光的测量：（1）介质中的光传输，它描述了返回光纤的光量；（2）与光纤的光耦合，这取决于进入光纤的光子的角分布。我们关注后一个因素的重要性，并描述耦合效率如何取决于介质的光学特性。对于高散射组织，光纤的数值孔径（NA）能很好地预测耦合效率。对于较低散射的情况，比如在软组织中，光子从更深的深度到达光纤，耦合效率可能比由数值孔径预测的值高出两倍到三倍。
