Study on Two-Dimensional Exit Pupil Expansion for Diffractive Waveguide Based on Holographic Volume Grating
Diffraction gratings are becoming a preferred option for waveguide head-mounted in–out coupling devices due to their flexible optical properties and small size and light weight. At present, diffraction waveguide coupling devices for AR head-mounted displays (HMD) have difficulties such as a long dev...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-10-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/13/21/11858 |
| _version_ | 1827765859045605376 |
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| author | Mianhui Weng Yizhao Wang Xuechang Ren Qinghong Lu |
| author_facet | Mianhui Weng Yizhao Wang Xuechang Ren Qinghong Lu |
| author_sort | Mianhui Weng |
| collection | DOAJ |
| description | Diffraction gratings are becoming a preferred option for waveguide head-mounted in–out coupling devices due to their flexible optical properties and small size and light weight. At present, diffraction waveguide coupling devices for AR head-mounted displays (HMD) have difficulties such as a long development cycle and complicated processing. In this paper, we first establish a set of two-dimensional (2D) grating ray tracing models, based on which we determine the initial architecture of the dual-region two-dimensional exit pupil expansion (2D-EPE) AR-HMD holographic waveguide diffraction system. Second, we propose a honeycomb coupled grating array and optimize the optical energy utilization and brightness uniformity of the holographic waveguide and use a custom dynamic linked library (DLL) function to implement the ray tracing of the 2D grating and add a probabilistic splitting function to the DLL, which reduces the single simulation time from 11.853 min to 1.77 min. We also propose a holographic lithography device composed of holographic optical elements (HOEs) and a method for preparing HOEs. Finally, in order to obtain the diffraction efficiency preoptimized by the above DLL for the uniformity of the exit pupil brightness and light energy utilization, we inverse design with the preparation process parameters as the optimization variables and develop the adaptable electromagnetic calculation program Holo-RCWA. Using Holo-RCWA with nondominated sorting genetic algorithm II (NSGA-II), we inverse design to obtain the process parameters satisfying the diffraction efficiency distribution, and the optimization time of the whole system is reduced from 2–3 days to 10 h. This work is of great significance for AR/VR applications. |
| first_indexed | 2024-03-11T11:33:46Z |
| format | Article |
| id | doaj.art-9adabfe6f3c44c90a15139ee5abfae7e |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-11T11:33:46Z |
| publishDate | 2023-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-9adabfe6f3c44c90a15139ee5abfae7e2023-11-10T14:58:57ZengMDPI AGApplied Sciences2076-34172023-10-0113211185810.3390/app132111858Study on Two-Dimensional Exit Pupil Expansion for Diffractive Waveguide Based on Holographic Volume GratingMianhui Weng0Yizhao Wang1Xuechang Ren2Qinghong Lu3Holographic Optics Lab, School of Physical Science and Technology, Xiamen University, Xiamen 361005, ChinaHolographic Optics Lab, School of Physical Science and Technology, Xiamen University, Xiamen 361005, ChinaHolographic Optics Lab, School of Physical Science and Technology, Xiamen University, Xiamen 361005, ChinaHolographic Optics Lab, School of Physical Science and Technology, Xiamen University, Xiamen 361005, ChinaDiffraction gratings are becoming a preferred option for waveguide head-mounted in–out coupling devices due to their flexible optical properties and small size and light weight. At present, diffraction waveguide coupling devices for AR head-mounted displays (HMD) have difficulties such as a long development cycle and complicated processing. In this paper, we first establish a set of two-dimensional (2D) grating ray tracing models, based on which we determine the initial architecture of the dual-region two-dimensional exit pupil expansion (2D-EPE) AR-HMD holographic waveguide diffraction system. Second, we propose a honeycomb coupled grating array and optimize the optical energy utilization and brightness uniformity of the holographic waveguide and use a custom dynamic linked library (DLL) function to implement the ray tracing of the 2D grating and add a probabilistic splitting function to the DLL, which reduces the single simulation time from 11.853 min to 1.77 min. We also propose a holographic lithography device composed of holographic optical elements (HOEs) and a method for preparing HOEs. Finally, in order to obtain the diffraction efficiency preoptimized by the above DLL for the uniformity of the exit pupil brightness and light energy utilization, we inverse design with the preparation process parameters as the optimization variables and develop the adaptable electromagnetic calculation program Holo-RCWA. Using Holo-RCWA with nondominated sorting genetic algorithm II (NSGA-II), we inverse design to obtain the process parameters satisfying the diffraction efficiency distribution, and the optimization time of the whole system is reduced from 2–3 days to 10 h. This work is of great significance for AR/VR applications.https://www.mdpi.com/2076-3417/13/21/11858diffraction waveguideholographic gratingtwo-dimensional exit pupil expansion |
| spellingShingle | Mianhui Weng Yizhao Wang Xuechang Ren Qinghong Lu Study on Two-Dimensional Exit Pupil Expansion for Diffractive Waveguide Based on Holographic Volume Grating Applied Sciences diffraction waveguide holographic grating two-dimensional exit pupil expansion |
| title | Study on Two-Dimensional Exit Pupil Expansion for Diffractive Waveguide Based on Holographic Volume Grating |
| title_full | Study on Two-Dimensional Exit Pupil Expansion for Diffractive Waveguide Based on Holographic Volume Grating |
| title_fullStr | Study on Two-Dimensional Exit Pupil Expansion for Diffractive Waveguide Based on Holographic Volume Grating |
| title_full_unstemmed | Study on Two-Dimensional Exit Pupil Expansion for Diffractive Waveguide Based on Holographic Volume Grating |
| title_short | Study on Two-Dimensional Exit Pupil Expansion for Diffractive Waveguide Based on Holographic Volume Grating |
| title_sort | study on two dimensional exit pupil expansion for diffractive waveguide based on holographic volume grating |
| topic | diffraction waveguide holographic grating two-dimensional exit pupil expansion |
| url | https://www.mdpi.com/2076-3417/13/21/11858 |
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