Although SHG microscopy has intrinsic optical sectioning, it is not a true 3D modality as fibers with axes that lie along the direction of laser propagation are transparent to SHG as the interaction is electric dipole forbidden. As such, current SHG microscopy could miss important information and does not provide a full tomographic image of the collagen structure in biological tissue. Previously a stage-insertable platform was developed that rotates the sample to allow for multiview SHG imaging such that any fibers missing in any single view would be visualized in another. While the initial reconstruction method resulted in a reasonable tomographic view of rat tail tendon, it did not perform as well on other, less aligned tissues. However, evaluating reconstruction methods on experimental data is inherently difficult due to the lack of a ground truth. In this dissertation, a toy model of tomographic SHG imaging was developed through the derivation of the dependence of SHG intensity on the angle between the fiber and laser axes, which is then used to better examine the limitations of our current reconstruction methods. This model could be used to develop and evaluate new reconstruction methods leading to improved tomographic SHG imaging.
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Although SHG microscopy has intrinsic optical sectioning, it is not a true 3D modality as fibers with axes that lie along the direction of laser propagation are transparent to SHG as the interaction is electric dipole forbidden. As such, current SHG microscopy could miss important information and does not provide a full tomographic image of the collagen structure in biological tissue. Previously a stage-insertable platform was developed that rotates the sample to allow for multiview SHG imaging such that any fibers missing in any single view would be visualized in another. While the initial reconstruction method resulted in a reasonable tomographic view of rat tail tendon, it did not perform as well on other, less aligned tissues. However, evaluating reconstruction methods on experimental data is inherently difficult due to the lack of a ground truth. In this dissertation, a toy model of tomographic SHG imaging was developed through the derivation of the dependence of SHG intensity on the angle between the fiber and laser axes, which is then used to better examine the limitations of our current reconstruction methods. This model could be used to develop and evaluate new reconstruction methods leading to improved tomographic SHG imaging.