Design And Optimization Of Surface Relief Gratings Waveguide AR System Based On RCWA Method

AR waveguide is a kind of new virtual reality display technology.AR waveguide transmits light through diffraction spectroscopy of diffractive optical elements,and total internal reflection of geometric optics in the waveguide.AR waveguide plays an important optical effect in small structure,light weight and no shading in optometry machine,which performs great consumption potential.Above all,the surface relief grating has become popular in the current AR waveguide solutions,due to its high degree of freedom,high diffraction efficiency and good reproducible properties.In the present AR waveguide design community,simulation commercial softwares on the market can only direct at one of physical optics and geometric optics,but both of them are involved in simulation design,which results in deficiency in efficiency and functionality.This paper realize the physical optics simulation of surface relief grating,which is based on the Rigorous coupled-wave analysis,RCWA.In addition,this paper design a geometric optical simulation suitable for waveguide.This paper establish the optical models of 1D pupil dilation and 2D pupil dilation through formula derivation and angle calculation,and implement a waveguide simulation algorithm which combines physical optics and geometric optics on C++platform.The presented simulation algorithm is verified by commercial software COMSOL to ensure the accuracy of simulation results,by multiplexing the above procedures.Finally the propagation and imaging of light in the case of full Field of View(FOV)and large amount of lights are simulated.In this passage,the computing speed of light propagating in waveguide is optimized,which based on depth-first search algorithm and hash table storage.The speed of light position determination based on the improved rotation vector method is also optimized.In this paper,an optimization program is designed based on genetic algorithm,and the astringency of the surface relief grating optimization program could be greating enhanced by way of interfering the genetic mode of offspring.Through the study of surface relief grating diffraction characteristics,the shoot light propagation results after multiple sets of grating are given,as well as the diffraction characteristic curve.The optimization is conducted through the whole FOV,in addition,this paper put forward a way of improving diffraction efficiency of the whole mission,by decoupling the two groups of coupled grating respectively to take part of the diffraction task.The results show that under the condition of full FOV at 30°×30°,the include incident diffraction efficiency up to 0.677,and the size of the decoupling dilated pupil at 12mm × 12mm,the image quality on the image plane is basically uniform.This paper provides a program of AR waveguide design and simulation for surface relief grating,which is based on strict coupled wave analysis.A set of optimization results are given in combination with the optimization algorithm.The program combines optimization and simulation,whitch shows great effects in AR waveguide design field.