Polarization-modulated second harmonic generation in collagen
Polarization-modulated second harmonic generation in collagen
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DOI：
10.1016/s0006-3495(02)75673-7
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发表时间：
2002-06-01
影响因子：
3.4
通讯作者：
Rubenchik, AM
中科院分区：
文献类型：
--
作者：
Stoller, P;Reiser, KM;Rubenchik, AM
胶原蛋白具有很强的二阶非线性极化率，这是一种非线性光学性质，其特征在于在强激光束存在下产生二次谐波。我们提出了一种新的技术，涉及偏振调制的超短脉冲激光束，可以同时确定胶原纤维的取向和相关的二阶非线性极化率的参数。我们证明了区分不同模式的纤维取向的能力，例如肌腱，筋膜，角膜，和椎间盘中连续的板层环。纤维取向可以作为深度的函数进行测量，轴向分辨率接近10 μ m。与二阶非线性极化率相关的参数对光纤的破坏、光束斜入射到样品上以及组织的双折射敏感。该参数表示可能用于体内光学成像的组织光学特性的总体测量。
Collagen possesses a strong second-order nonlinear susceptibility, a nonlinear optical property characterized by second harmonic generation in the presence of intense laser beams. We present a new technique involving polarization modulation of an ultra-short pulse laser beam that can simultaneously determine collagen fiber orientation and a parameter related to the second-order nonlinear susceptibility. We demonstrate the ability to discriminate among different patterns of fibrillar orientation, as exemplified by tendon, fascia, cornea, and successive lamellar rings in an intervertebral disc. Fiber orientation can be measured as a function of depth with an axial resolution of similar to10 mum. The parameter related to the second-order nonlinear susceptibility is sensitive to fiber disorganization, oblique incidence of the beam on the sample, and birefringence of the tissue. This parameter represents an aggregate measure of tissue optical properties that could potentially be used for optical imaging in vivo.