在基於體積全像光柵（Volume Holographic Optical Element, VHOE）之 光波導系統中，耦入端（Couple-In）光柵的設計參數對波導內光傳輸效率與 具有關鍵性影響。其中，耦入區域的幾何尺寸，特別是其寬度參數，對於光 場在全像結構中的繞射行為，尤其是二次繞射現象，具有顯著作用。然而， 現有文獻中對此參數與二次繞射之間的關聯性尚缺乏系統性與量化的探討。 本研究以波長 532 nm 的綠光雷射進行光柵紀錄，針對 VHOE 耦合結 構進行不同寬度條件下之設計與實驗實作。透過控制耦入區域寬度，分析其 對二次繞射強度影響機制，並建構相關參數對應模型。實驗結果顯示，耦合 寬度對二次繞射確實產生影響，但是有更多不可控之因素導致光導效率與 理論不相符。 本研究成果揭示了二次繞射效應之理論計算與實驗不匹配之情況，並 重新對二次繞射理論值計算做修正，修正後之理論值與實際值接近，為後續 研究對二次繞射之計算奠定基礎。;In waveguide systems based on Volume Holographic Optical Elements (VHOE), the design parameters of the couple-in grating play a critical role in determining the light transmission efficiency within the waveguide. Among these, the geometric dimensions of the coupling region—particularly its width—have a significant effect on the diffraction behavior of the light field within the holographic structure, especially regarding secondary diffraction. However, existing literature lacks systematic and quantitative investigations into the relationship between this parameter and secondary diffraction. In this study, a green laser with a wavelength of 532 nm was used for grating recording, and various width conditions of the VHOE coupling structure were designed and experimentally implemented. By controlling the width of the coupling region, we analyzed its influence on secondary diffraction intensity and constructed a corresponding parameter model. Experimental results indicate that the coupling width indeed affects secondary diffraction, though numerous uncontrollable factors led to discrepancies between waveguide efficiency and theoretical predictions. This study reveals inconsistencies between theoretical calculations and experimental results of secondary diffraction effects and presents a revised calculation model for secondary diffraction values. The corrected theoretical values show close agreement with experimental data, laying a foundation for future research on the calculation of secondary diffraction.
