平面波导系统中线性光栅的设计与分析
|
摘要
针对平面波导系统中光能利用率低、光栅制备成本高且工艺复杂的问题,设计大周期、高衍射效率的光栅结构,从而提高系统光效、节约成本。首先,提出以梯形光栅作为最初面型进行标量理论计算,以梯形的角度、占空比、高度为变量,得出光栅面型为直角三角形时,-1级有较高衍射效率。随后分析了设计的直角三角光栅和两种常见的线性光栅的衍射效率,并且讨论了深度加工误差、入射光发散角对三种面型光栅衍射效率的影响。仿真结果显示:周期为3μm的直角三角光栅,入射光垂直入射时-1级衍射效率达81%,与小周期倾斜光栅的衍射效率相差较小,但考虑到深度加工误差和入射光的发散角度对三种面型光栅衍射效率的影响时,直角三角光栅则具有明显优势。设计的直角三角光栅在具有较大周期时,仍可实现较高衍射效率。
Aiming at the problems of low light energy efficiency,high fabrication cost and complicated process,a kind of grating structure with large period and high diffractive efficiency was designed to improve system light efficiency and save cost.Firstly,based on scalar theory,the trapezoidal grating was put forward as the initial surface shape.The angle,duty cycle and depth of the trapezoid grating were used as variables to analyze the diffraction efficiency.It is found that the right triangular grating presents the higher efficiency at-1 st order.Then the dif-fraction efficiency of the designed right triangular grating and two common linear gratings were simulated as well as the effects of depth error and incident light divergence angle on the diffraction efficiency.Simulation results show that the diffraction efficiency at the-1 st order of the right triangular grating with a period of 3μm is 81% when the incident light is normal-incidence,which is slightly less than the diffraction efficiency of the small-period oblique grating.However,when considering the depth processing error and the divergence angle of the incident light,the right triangular grating presents the obvious advantage over the oblique grating.The right triangular grating designed could achieve higher diffraction efficiency with a large period.
Aiming at the problems of low light energy efficiency,high fabrication cost and complicated process,a kind of grating structure with large period and high diffractive efficiency was designed to improve system light efficiency and save cost.Firstly,based on scalar theory,the trapezoidal grating was put forward as the initial surface shape.The angle,duty cycle and depth of the trapezoid grating were used as variables to analyze the diffraction efficiency.It is found that the right triangular grating presents the higher efficiency at-1 st order.Then the dif-fraction efficiency of the designed right triangular grating and two common linear gratings were simulated as well as the effects of depth error and incident light divergence angle on the diffraction efficiency.Simulation results show that the diffraction efficiency at the-1 st order of the right triangular grating with a period of 3μm is 81% when the incident light is normal-incidence,which is slightly less than the diffraction efficiency of the small-period oblique grating.However,when considering the depth processing error and the divergence angle of the incident light,the right triangular grating presents the obvious advantage over the oblique grating.The right triangular grating designed could achieve higher diffraction efficiency with a large period.
引文
[1] Gao Yuan,Liu Yue,Cheng Dewen,et al.A review on development of head mounted display[J].Journal of ComputerAided Design&Computer Graphics,2016,28(6):897-904.
[2] Takashi Shibata.Head mounted display[J].Displays,2002,23(1-2):57-64.
[3] Hiroshi Mukawa,Katsuyuki Akutsu,Ikuo Matsumura,et al.A full-color eyewear display using planar waveguides with reflection volume holograms[J].Society for Information Display,2009,17(13):185-193.
[4] Shi Rui,Liu Juan,Zhao Haozhi,et al.Chromatic dispersion correction in planar waveguide using one-layer volume holograms based on three-step exposure[J].Optical Society of America,2012,51(20):4703-4708.
[5] Wu Zhengmin,Liu Juan,Wang Yongtian.High efficiency waveguide display system with achromatic volume hologram and a prism in-coupler[J].Society for Information Display,2013,44(1):888-890.
[6] Guo Jingjing,Tu Yan,Yang Lanlan,et al.Waveguide display with combined-grating in-couplers[J].Applied Optics,2016,55(32):9293-9298.
[7] Han Jian,Liu Juan,Yao Xincheng,et al.Portable waveguide display system with a large field of view by integrating free form elements and volume hologram[J].Applied Optics,2015,23(3):3534-3549.
[8] Shen Zhongwen,Zhang Yuning,Weng Yishi,et al.Characterization and optimization of field of view in a holographic waveguide display[J].IEEE Photonics Journal,2017,9(6):1943-0655.
[9] Kiyoshi Yokomori.Dielectric surface-relief gratings with high diffraction efficiency[J].Applied Optics,1984,23(14):2303-2310.
[10]Michael J Miller,Nicole de Beaucoudrey,Pierre Chavel,et al.Design and fabrication of binary slanted surface-relief gratings for a planar optical interconnection[J].Applied Optical,1997,36(23):5717-5727.
[11]程鑫.头盔显示系统中全息波导技术研究[D].合肥:合肥工业大学,2018.
[2] Takashi Shibata.Head mounted display[J].Displays,2002,23(1-2):57-64.
[3] Hiroshi Mukawa,Katsuyuki Akutsu,Ikuo Matsumura,et al.A full-color eyewear display using planar waveguides with reflection volume holograms[J].Society for Information Display,2009,17(13):185-193.
[4] Shi Rui,Liu Juan,Zhao Haozhi,et al.Chromatic dispersion correction in planar waveguide using one-layer volume holograms based on three-step exposure[J].Optical Society of America,2012,51(20):4703-4708.
[5] Wu Zhengmin,Liu Juan,Wang Yongtian.High efficiency waveguide display system with achromatic volume hologram and a prism in-coupler[J].Society for Information Display,2013,44(1):888-890.
[6] Guo Jingjing,Tu Yan,Yang Lanlan,et al.Waveguide display with combined-grating in-couplers[J].Applied Optics,2016,55(32):9293-9298.
[7] Han Jian,Liu Juan,Yao Xincheng,et al.Portable waveguide display system with a large field of view by integrating free form elements and volume hologram[J].Applied Optics,2015,23(3):3534-3549.
[8] Shen Zhongwen,Zhang Yuning,Weng Yishi,et al.Characterization and optimization of field of view in a holographic waveguide display[J].IEEE Photonics Journal,2017,9(6):1943-0655.
[9] Kiyoshi Yokomori.Dielectric surface-relief gratings with high diffraction efficiency[J].Applied Optics,1984,23(14):2303-2310.
[10]Michael J Miller,Nicole de Beaucoudrey,Pierre Chavel,et al.Design and fabrication of binary slanted surface-relief gratings for a planar optical interconnection[J].Applied Optical,1997,36(23):5717-5727.
[11]程鑫.头盔显示系统中全息波导技术研究[D].合肥:合肥工业大学,2018.