| With the development of materials and technologies,nanometer scale metal films have played a vital role in the fields of photoelectric,micro electro-mechanical,aviation engineering and biological detection.The thickness and optical constants of the metal films are not only the main parameters that affect the properties of the thin film,but also the important factors to characterize quality and optical properties of film.Thus,the measurement of nanometer-scale metal film thickness and optical constants has extremely high research value.Because the surface plasma effect can sensitively perceive the change of interface surface properties,and has the characteristics of noncontact and high detection sensitivity like ellipsometry,which can be used to measure the characteristic parameters of thin film materials.At the same time,the sensitivity of this method is higher than that of spectrophotometry,and it can be improved by enhancing SPR effect.Based on the above discussion and the research foundation of the group on measuring the thickness of metal thin film by SPR phase method,study the enhancement method based on SPR phase method,and to carry out the measurement method and application of film material thickness and optical constants are proposed as the main research contents of this dissertation.The completed work mainly includes:Research on multiple internal reflections used to enhance SPR effect.Through the dispersion characteristics of metal materials and SPR measurement principles,a theoretical model for measuring the thickness of metal thin films using the multiple internal reflection SPR phase method is established,and the principle of multiple internal reflection enhancing SPR effect is analyzed.Then,the corresponding optical detection system is designed and built according to the measurement model.The method of obtaining the phase difference including the thickness information of metal film through the interference fringe image is determined,and the corresponding experiment is carried out on the thickness of the single-layer gold film.The calibration scheme of comparison test using ellipsometer is designed to verify the experimental results.Besides,the error source of the detection method and the feasibility of improvement or correction are analyzed,which provides a new idea for further study of film related parameters.Research on reverse engineering algorithm of multi-layer thickness and optical constants.A reverse engineering algorithm based on SPR phase method is developed to detect the thickness and optical constants of multi-layer films.The construction strategy of algorithm is given,and the inversion model of the thickness and optical constants of the multilayer films is established.Through the analysis of reverse engineering experiments of single-layer gold film and double-layer gold silver film SPR phase method,the inversion results are compared with those of particle swarm optimization algorithm and ellipsometer respectively.The calculation performance of proposed hybrid algorithm and the reliability of inversion results are verified,which provides a new path for the calculation of multilayer film thickness and optical film.Study on SPR effect enhanced by composite structure of metal film and two dimensional material.The exciation method of SPR effect enhanced by new twodimensional materials are studied,based on the structure of traditional single-layer metal film and double-layer metal film SPR prism structure,a design method of highsensitivity phase SPR sensor is proposed.The structure of each layer of the sensor is optimized by mathematical model,and the performance of the SPR biosensor is verified by simulation experiments.This composite structure,which combines new twodimensional materials with traditional nano scale metal film,further improves the measurement sensitivity of SPR sensor. |
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