Monte Carlo simulation of polarization‐sensitive second‐harmonic generation and propagation in biological tissue

Abstract

Polarization-sensitive second harmonic generation (p-SHG) is a nonlinear optical microscopy technique that has shown great promise in biomedicine, such as in detecting changes in the collagen ultrastructure of the tumor microenvironment. However, the complex nature of light-tissue interactions and the heterogeneity of biological samples pose challenges in creating an analytical and experimental quantification platform for tissue characterization via p-SHG. We present a Monte Carlo (MC) p-SHG simulation model based on double Stokes-Mueller polarimetry for the investigation of nonlinear light-tissue interaction. The MC model predictions are compared with experimental measurements of second-order nonlinear susceptibility component ratio and degree of polarization (DOP) in rat-tail collagen. The observed trends in the behavior of these parameters as a function of tissue thickness, as well as the overall extent of agreement between MC and experimental results, are discussed. High sensitivities of the susceptibility ratio and DOP are observed for the varying tissue thickness on the incoming fundamental light propagation pathway.

Characterization of Pancreatic Cancer Tissue Using Multiphoton Excitation Fluorescence and Polarization-Sensitive Harmonic Generation Microscopy

“…The influence of birefringence and scattering due to SHG propagation through birefringent tissue regions can be considered as negligible, since the tissue sections are sufficiently thin (5 μm) that there is minimal cumulative retardation of the light. An additional assumption that the scattering of the polarized SHG light is negligible is also reasonable, considering that the tissue samples are all the same thickness (60). The DOLP for normal periductal and parenchymal tissues were significantly different than for tumor ( p < 0.002 and p < 0.01, respectively).…”

Band selection for mapping chromophores of skin tissue

“…From the above description it can be found that the problem of band selection for optimal imaging of the chromophores of biological tissue is task dependent and still remains unresolved. Most of the studies conducted so far were based on numerical simulation of light interacting with tissue via the Monte Carlo or Ray tracing method, in which all possible components involved in an imaging process such as illumination, chromophores underneath tissue surface as well as optical sensor are modeled [16]. This computing based simulation is flexible and easy to conduct, however they are not straight related to the robustness of inverse estimation of chromophores under different band combination [17,18].…”

Study of a bi-axial (KTP) crystal using Double Stokes Mueller Polarimetry

“…Monte Carlo polarization-sensitive SHG simulation model based on DSMP is used to study nonlinear light interaction with tissues. This theoretical model prediction are compared with the DSMP measurements performed in rat tail collagen [32]. The R-ratio of myosin fibrils of Drosophila melanogaster larva is studied using incoming and outgoing circular polarization states in DSMP technique [33].…”