The Use of Second-Order Susceptibility as Contrast Mechanism for Label-Free Imaging of Biological Tissue

This review paper conveys state-of-the art research on second-order susceptibility microscopy: physical origin, devices and instrumentation, applications in biological system, and prospects of clinical applications. The organization of this paper started with an overview of second harmonic generation (SHG) in biological medium. Illustrating with figures system architecture of second-order susceptibility and manipulation of polarization are introduced, which is the central scheme in this imaging modality. Several applications of SHG susceptibility imaging in biological and biomedical sciences are then discussed. This review paper is finally concluded with future prospects of susceptibility imaging in clinical settings.