Study On The Performance Of Polarization Beam Splitting Gratings

Micro-nano grating is a very basic periodic optical element in optical system,which has a wide range of applications in various micro-nano optical devices.With the development of micro-nano optics and integrated circuit,grating is gradually combined with other optical components to make on-chip grating-based high-precision optical instruments.This also requires the micro-nano gratings to be more miniaturized,high precision,powerful performance and easy to manufacture.In this thesis,micro-nano gratings are developed based on rigorous coupled-wave analysis,modal method and finite element theory.The main work such as:(1)Aiming at the stable performance of grating,a single channel diffraction grating with a covering layer is designed under second Bragg mounting.The grating can diffract the energy of the incident light to the-2 order,and the addition of the covering layer can make the performance of the grating stable.(2)Based on the grating groove embedded metal structure,a single channel diffraction grating with metal embedded under second Bragg mounting is designed.Because the grating has good fabrication tolerance and incident characteristics,it can be well applied in laser field.(3)In order to achieve a single grating to achieve a variety of diffraction functions,a dual-function polarization beam splitting diffraction grating is proposed in second-order Littrow mounting.The device can diffract TE-polarized light to 0 order,and diffract TMpolarized light uniformly to 0 order and-2 order.Therefore,the grating achieves dualfunction polarization beam splitting effect and can be applied in many optical systems.(4)Based on metal coating structure,a metal-coated grating with oblique incidence is proposed.The device reflects TE-polarized light at diffraction 0 order and transmits TMpolarized light at diffraction 0 order.The proposed device can be integrated into a liquid crystal display due to its small size and high anti interference capability.(5)Based on T-shaped grating structure,five-channel grating with T-shaped arrays is presented.The five diffraction efficiencies of TE and TM-polarized light are all over 17%.The reflection efficiency of five-channel grating is over 92% with good uniformity,which can be widely used in laser field.(6)Aiming at the problem of high order diffraction of excited grating,the sevenchannel grating is designed with T-shaped arrays.The efficiency of each order reaches 14%,and the total transmission efficiency is more than 92%.The device can be used to develop the novel multi-channel power beam splitter.(7)Based on three-layer rectangular grating structure,a compact high-efficiency silicabased nine-channel beam splitter grating(BSG)at infrared wavelength is proposed based on a three-layer array structure.The total efficiency of the nine-channel beam splitter reaches96%,and the error of uniformity is reduced to 3%.The gratings can be used in ultraprecision optical devices with multiple beam separation.