Measurement Of Optical Material Dispersion By Ellipsometry

Elliptical polarization technology is widely used in materials analysis,optical manufacturing and other research fields.In order to detect the refractive index of optical materials on the production line quickly,In this paper,ellipsometry is used to carry out the previous research.The subject is to study the dispersion of materials in the visible light band.The refractive index of optical materials is measured by the polarization state between incident and reflected light in ellipsometry,choose the experimental instrument and build the experimental platform,the refractive index of the material at the wavelength of 486.1nm?589.3nm and 656.3nm was measured,and the dispersion of the material was analyzed.The main findings are as follows:?1?By comparing the merits and demerits of different methods in measuring refractive index,it is concluded that the ellipsometry method has advantages in sample processing for studying the properties of optical materials,and it is only necessary to process the surface of the sample into a plane.The angulation method of ellipsometry is analyzed,and the extinction method is chosen to measure the refractive index of materials.?2?Based on ellipsometry theory,the dispersion model of optical material is established,and the influence factors of measuring refractive index are simulated.The influence of wavelength,incident angle,optical axis direction of polarizer and vibration direction of linearly polarized light on the measurement accuracy is analyzed.It is concluded that the angle of incidence is 60^?,the angle of deviation is 45^?,and the precision of angle measurement is high.?3?The simulation results are verified by He-Ne laser,and the experimental results are in agreement with the simulation results.The grating Monochromator splits the light source and measures the refractive index of the sample at three wavelengths.The conventional V-prism method is used to measure the refractive index of the sample,which is used as the reference value for error analysis of the experimental results of ellipsometry.It is found that the overall effect of different error sources on the refractive index measurement results is1×10^-4,which makes the experimental results meet the design requirements.?4?According to the measurement principle,a narrow-band filter and a polarizer with two polarization directions perpendicular to each other are designed in front of the array detector,which can eliminate the refractive index measurement error caused by the fluctuation of the light source and improve the angle measurement accuracy.