Study On Sensing Characteristics Of Mirror Porous Silicon Photonic Crystal

After more than 20 years of research and development,the research topic of photonic crystal has been developed from the stage of the discovery of dielectric materials and the theory research to how to apply photonic crystal to various fields of photoelectric technology today.It is a common objective of contemporary photonic crystal researchers that how to design excellent optical elements by using photonic band gap and photon local conditions of photonic crystals.Optical technology has a wide range of applications in biomedical diagnosis,national defense scientific research,monitoring and early warning of flammable and explosive materials in the environment,because of its strong anti-interference ability,rapid detection and high reliability.This paper proposed a new refractive index sensing structure based on mirror porous silicon photonic crystal and the refractive index sensing characteristics is analyzed,compared with the one-dimensional photonic crystals with defects.The main research work is as follows:Firstly,a kind of mirror porous silicon photonic crystal refractive index sensing structure is proposed by combining the local characteristics of photonic crystals with the specific optical properties of porous silicon.Based on the sensor theory model established by transfer matrix method,the relationship between the defect wavelength and its basic structure parameters is obtained.By Modifying the structural parameters of the high and low refractive index layers of the porous silicon,the FWHM of defect peak turns narrow,and then the quality factor(Q value)can be improved.Secondly,a hybrid mirror porous silicon photonic crystal sensor combined with the chirped photonic crystal structure is proposed,which is based on the tight binding theory.And then the relationship model between resonant wavelength and the gas refractive index is established using optical resonance theory and tight binding theory.What is more,the sensor characteristic is analyzed.Finally,according to the transfer matrix theory,this paper conducts the theoretical simulation when different concentrations of methanol vapor penetrate into the sensing structure and the spectral properties is summarized by observing the spectrum.What is more,the relationship between the change of equivalent refractive index and the wavelength of defect peak is derived.The hybrid mirror porous silicon photonic crystal sensor is compared with the single mirror,and the result shows that the Q value and sensitivity were improved,which Certificates its effectiveness and application potential.