Study On Infrared Radiation Effect Of Biological Tissue

Electromagnetic wave technology is developing at a high speed,and the research of bioelectromagnetics is progressing continuously.Infrared is widely used in biological and medical fields,including optical tweezers,infrared medical imaging and infrared laser surgery.Complex skin,which is the barrier of the human body,is the organ that electromagnetic waves must through when radiates human body.The study of the electromagnetic wave effect of skin is the basic link of the Bioelectromagnetics research of human tissue.This thesis mainly studied the transmission effect of infrared penetrating human skin.Firstly,the layered physiological structure of human skin was introduced in detail,and based on its layered physiological structure,the transmission characteristics of infrared in human skin were analyzed.The absorption characteristics of human skin in the infrared band were analyzed by using the absorption spectra of hemoglobin,water and melanin,which are the main absorption components of human skin.The dispersion curves of refractive index and complex dielectric constant of skin tissue in infrared band were given.Secondly,the transmission characteristics of infrared in human skin were studied by two methods.One is based on the layered stacking structure of human skin and the theory of thin film optics,two idealized periodic structure models were established for epidermis and dermis,and the eigen matrix formula of one-dimensional periodic structure of skin was deduced.Then the influence of incident angle of infrared,dispersion of refractive index and thickness on human skin radiated by infrared is analyzed by using the eigen matrix method.Another one is based on the traditional theory of transmission matrix method,the formulas of transmission matrix method for ordinary layered media were deduced.And the electromagnetic properties of two ideal skin tissue models including the single layer structure without intercellular stroma and the three-layer structure with intercellular stroma were analyzed by the transmission matrix method.The influence of incident angle,dispersion and thickness on the electromagnetic properties of the two structures in the infrared band were analyzed.For the three-layer structure,the influence of stroma thickness was also analyzed.Finally,a full-wave numerical simulation model of infrared transmitting in human skin was established,which was based on the Finite-Difference Time-Domain(FDTD)simulation model of dispersive media.Skin is Debye dispersive medium.The Debye parameters of human skin in the infrared frequency band were obtained from the literature.In this paper,RC-FDTD and PLRC-FDTD simulation models were studied.The attenuation,reflection and transmission properties of infrared in skin were analyzed based on the simulation results.