| Optical particle detection technology has important research value and a wide range of applications in pharmaceutical, chemical, nano optoelectronics and other scientific fields. But it is very difficult to extract the weak signal from the background noise by the optical method. Particle size resolution is a very important concept in particle detection. It represents the smallest scale that can be resolved in the measurement. In the field of biomedical engineering, we often need to analyze the image.The higher the resolution is, the more conducive the extraction of information is, then how to improve the resolution has become an inevitable topic. Optical resolution, also called optical resolution, is referred to the actual amount of information which can be collected in optical system of the instrument, it is one of the key indicators to measure the optical instrument grade. Ordinary optical microscope resolution can be up to half of the visible light wavelength. In order to achieve the goal of improving optical resolution, the paper come up with the method for improving the resolution of the amplitude and phase distribution of the scattered light field based on the interaction between the double nano particles and the high concentration light spot. Based on the preliminary design of the project group, orthogonal polarization microscopy imaging system can achieve high sensitivity of detection, and in the unmarked case we get individual nanoparticles and light interaction of light scattering field for four petal shaped structure under the premise. According to the two particle changes in different amplitude and phase distribution in different locations and different distance, the paper can determine the relative position of the two particles and improve the resolution of the particle effect at the same time.This paper studies the use of polystyrene particles, because it has a similar optical properties with the biological environment and can simulate the biological system. First of all, The amplitude and phase distribution image of the scattered light field obtained by the interaction between the high concentration and the two nanoparticles are studied. It is mainly based on orthogonal polarization and external interference method, Based on the scattered light field of the single particle obtained by the previous research group with the help of the interaction of the particle and the light, the polystyrene material will not be coupled. Therefore, the scattered light field can be superimposed., The scattered light field amplitude and phase distribution of the two nanoparticles in Y direction were alsoobtained. Secondly, Numerical simulation is carried out and we verify the result by FDTD algorithm using Mie scattering method., We analyse the variation of the amplitude and phase distribution of the scattered light field of the two nanoparticle., According to the different amplitude and phase distribution of the two particles at different location, we can determine the relative position relation of two particles. Experiments were carried out by means of orthogonal polarization microscopy imaging system. The experimental results and simulation results are compared with the simulation results. The paper verify the feasibility of the simulation results, and ultimately improve the resolution results.The innovation of this paper:(1) Through the comparison of numerical simulation and experimental results, it achieve two polystyrene particles with a diameter of only 100nm. The optical resolution of the incident light wavelength of 632.8nm can reach the center distance of 200nm. That is to say, the distance between the two nanoparticles was 100nm and finally improve optical resolution In the simulation process; (2) the distance between the two nanoparticles ranged from 100-400nm. A method for determining the relative position of two nanoparticles is finally determined based on the amplitude and phase distribution of the scattered light field of the two nanoparticles. |
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