Multi-spectral Measurement Of Optical Parameters Of Turbid Media

The interaction between light and matter is mainly absorption and scattering Due to the strong scattering of turbid materials,such as cell suspensions,biological tissues,blood,food,crops,soil,and environmental sewage,the differences in the molecular structure result in a difference in absorption and scattering.So,the absorption and scattering signals contain rich material information.It can be used in the fields of analytical chemistry,material research,food and pharmaceutical inspection,environmental monitoring and clinical diagnosisThe optical parameters of the turbid medium can accurately describe the propagation and distribution of light in the medium and the interaction between the light and the medium,and it is the basic physical quantity of the radiation transmission model.It is of great significance to accurately measure the optical parameters of materials.In this paper,a multispectral measurement method for optical parameters of turbid media based on radiation transmission theory is proposed.An experimental measurement system is designed and constructed,and the optical parameters of polystyrene microspheres are measured.The contents are as follows:First,based on the radiation transmission model,an individual photon tracking Monte Carlo method was designed and coded,and a three-signal light scattering positive problem solving model was established.Under a given turbid medium absorption coefficient,scattering coefficient and anisotropic parameter,three simulations of detector signal were obtainedSecond,a multi-spectral scattered light signal measurement experimental system is built.The system consists of three parts:spectral grating light source,weak signal measurement and sample measurement.The system is calibrated,and the three-detector experiment data of microsphere suspension is obtained by this systemThird,using the measured scattering signal,through the inverse calculation of the simulation model,the microsphere optical parameters were obtained,and the obtained results were compared with the Mie theoretical results,it is found that the?s and g obtained from the inversion are basically consistent with the ?sm and gm calculated according to Mie theory,but there is an error for both ?a,which is due to the imaginary part of the refractive index of the material used by Mie theoryFinally,different scattering phase functions were used to compare the optical parameters of the turbid medium,and the effects of phase functions on the extraction of optical parameters were further exploredThis measurement method does not require an integrating sphere device,does not need to measure the attenuation of a turbid medium,and only requires one sample,which has the characteristics of simple measurement.The continuous improvement of multi-spectral measurement of optical parameters can provide potential applications in qualitative and quantitative analysis of turbid media such as biological tissues,medicines and foods.