| Pancharatnam-Berry phase optical elements(PBOEs)generate phase shift by the spatial variation,instead of optical path difference.In theory,the diffraction efficiency of PBOEs can reach 100%.Therefore,PBOEs have great potential for optical switches,virtual reality(VR)displays and augmented reality(AR)displays.PBOEs based on LCs have excellent performance in switching.However,most of the researches on PBOEs mainly focus on the fabrication methods or diffraction efficiency,the response times of PBOEs have been ignored.For switchable elements,response time plays an important role in the practical application.Therefore,this dissertation aims at achieving fast-response PBOEs while ensuring its high diffraction efficiency.And the fabricated PBOEs have been used in AR displays.The research is mainly consisted of following two parts:1.The fabrication of fast-response Pancharatnam-Berry phase gratings(PBGs)and Pancharatnam-Berry phase lenses(PBLs)based on polymer-stabilized liquid crystal(PSLC).PBGs and PBLs can reach 100%in theory.However,they have poor performance in switching response.The demonstrated PBGs and PBLs based on PSLC both show high diffraction efficiencies and submillisecond response times,so they have great potential for various applications such as optical switching,beam steering,and AR displays.2.A varifocus lens based on fast-response PBLs for AR displays.At present,the stereoscopic technology is applied in most AR displays to provide 3D information,resulting in an accommodation-convergence conflict problem and dizziness.True 3D technology such as multi-plane display can provide correct depths information to solve the accommodation-convergence conflict problem.Based on the fast-response PBLs with high diffraction efficiency,we demonstrate a varifocus lens.And the varifocus lens is used in a compact,fast-switching multi-plane AR display system.This system can provide four correct depths information with submillisecond switching time. |
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