基于带宽匹配的复用体全息光栅设计  

Bandwidth Matching-Based Multiplexed Volume Holographic Grating

作　　者：冯奇斌[1] 蔡佳豪 郭裕嵩 郭敏 王梓 吕国强[2] Feng Qibin;Cai Jiahao;Guo Yusong;Guo Min;Wang Zi;LüGuoqiang(Special Display and Imaging Technology Innovation Center of Anhui Province,National Engineering Laboratory of Special Display Technology,Academy of Photoelectric Technology,Hefei University of Technology,Hefei 230009,Anhui,China;School of Instrument Science and Opto-Electronics Engineering,Hefei University of Technology,Hefei 230009,Anhui,China)

机构地区：[1]合肥工业大学特种显示与成像技术安徽省技术创新中心,特种显示技术国家工程实验室,光电技术研究院,安徽合肥230009 [2]合肥工业大学仪器科学与光电工程学院,安徽合肥230009

出　　处：《光学学报》2023年第22期65-71,共7页Acta Optica Sinica

基　　金：安徽省科技重大专项(202203a05020028)。

摘　　要：体全息光栅作为全息波导显示器的出/入耦合元件,其性能严重影响波导系统的视场。因其角度选择性,当光束偏离布拉格角入射体全息光栅时,其衍射光角度会产生较大的偏移,使得其与出耦合光栅的响应带宽不匹配,限制了波导系统的视场。首先基于Kogelnik理论对波导系统中体全息光栅的带宽匹配进行了分析。为了扩展波导系统的视场,提出了一种复用体全息光栅的设计方法。该设计旨在扩展出耦合光栅的响应带宽并同时收缩入耦合光栅的衍射光角度,使得出/入耦合光栅的带宽相匹配。仿真结果表明:采用本文设计的复用体全息光栅后,波导系统的视场能达到22.9°。本文设计的复用体全息光栅制备简单,可以有效拓展波导系统的视场。Objective The performance of a volume holographic grating as an incoupling/outcoupling element seriously affects the field of view(FOV)of a waveguide system.Many studies try to extend the incident angle response bandwidth of the volume holographic gratings to increase FOV.Most volume holographic gratings are designed based on the center ray.However,in a waveguide system,the collimation system converts the position information on the image source into angular information,which makes the beam incident to the volume holographic grating within a certain angle range(Δθ).Based on the Kogelnik theory,the angular range of the diffracted beamΔθ′is much larger thanΔθ.Since the diffracted beam of the incoupling grating is the incident beam of the outcoupling grating,the mismatch betweenΔθandΔθ′will make the outcoupling grating cannot fully receive all the angular information in the diffracted beam,causing insufficient transmitted image information.We propose a design method of multiplexed volume holographic gratings.The response bandwidth of the outcoupling grating is increased through multi-time multiplexing,while the diffraction angle offset range of the incoupling grating is reduced to match its bandwidth as much as possible,which can guarantee that enough image information can be received to increase the FOV of a waveguide system.Methods The analysis reveals that the factors limiting the FOV of the waveguide system include not only the response bandwidth of the volume holographic grating itself but also the bandwidth mismatch between incoupling grating and outcoupling grating.Therefore,a design method of multiplexed volume holographic gratings is proposed.The object and reference light preparation angles of a single grating are determined according to the total reflection condition of the waveguide.The diffraction efficiency corresponding to each of its angles is calculated,as well as the response bandwidth of the incoupling grating,the diffracted light angle of the incoupling grating,and the response band

关 键 词：体全息光栅 响应带宽 波导 复用 

分 类 号：TN27[电子电信—物理电子学]