Research On Effect Of Polarized Light In Imaging Quality Of Optical Imaging System

Along with the increasing of resolution of optical imaging system, the influence on imaging quality by the vectorial property of electric field can’t be ignored any more. Several polarization transmission matrixes are used in polarized ray trace on optical imaging system, diffraction spots along the three coordinates are calculated in method of Fourier transform, then the gross spot is the addition of these three components and unpolarized portion. This method is widely adopted in research of polarization imaging. Obviously, research on polarization could expand the limitation of imaging resolution, and that is the very goal of this project.In industry of fine lithography, in order to extend the limitation of lithography feature size, a variety of techniques have been developed, such as decreasing exposure wavelength, off-axis illumination for optical lithography, immersion lithography and increasing system NA etc. Methods mentioned here are quite effective and practical, but as long as the system NA is larger than0.75, the resolution is comparable to or smaller than the wavelength, because of ray inclination on the edge of aperture, vectorial feature of electric field has a remarkable influence on size and shape of diffraction spot. In this case, conventional scalar theory and method can’t meet the request now, and we must turn to the more accurate vectorial one. Theory based on vectorial electric field makes it possible that improving imaging quality through modulating polarization of imaging light, other than conventional amplitude and phase modulation.This article introduces research situation of polarization transmission and diffraction at home and abroad, then several common-used polarization matrixes along with their features and method to calculate them. Considering that Stokes vector can be used to describe all possible polarization states, we decide that Mueller matrix will be applied to express polarization related optical instrument or surface. Diffraction focussing between existing pupil and image plane is the way to calculate the point spread function (PSF) of the system, the largest difference between vectorial and scalar methods is reflected in here, therefore, the vectorial diffraction method has significant meanings for this research. Since polarization direction is always perpendicular to propagation direction, we adopt Debey Integral to calculate diffraction, which regards the electric field as plane waves that propagate in all directions. This kind of description of wave field is in favour of calculation of polarization. In the next part, this paper discusses several classic polarization distribution on the system aperture and derives the influence of these kinds of distribution on imaging quality. By the5th section, We will come into contact with work related to software programing, the related mathematical model, algorithm and data structure will be mentioned at first, program flow will be the second, last is analysis effects of the software. A real set of lithography lens which has really high NA will be showed to reader under analysis of polarization analysis software to evaluate practical value of the software module and the whole research project.