We report on an ultra-broadband three-layer dielectric transmission rectangle-groove grating with polarization-independence and high diffraction efficiency for −1st order under Littrow incidence. The all-dielectric grating consists of triple-layer grating ridges placed on the fused silica substrate. Next, the diffraction process is analyzed by using a simplified mode method and optimized parameters of the grating structure are calculated by using rigorous coupled analysis and a simulated annealing algorithm. The theoretical −1st order efficiencies of the transmission grating are more than 95% with incident wavelength ranging from 1446–1641 nm and incident angle ranging from 32.1–42.7 for both TE and TM polarizations, respectively. We also discuss that the great fabrication tolerances that depend on grating period and the thicknesses of the three dielectric layers ensure the high performance of the designed grating in the fabrication process. With the properties of ultra-broadband, high efficiency and polarization-independence, the designed rectangular all-dielectric grating should be of great interest for the most practical applications of dispersion.

我们报告了一种在 Littrow 入射下具有偏振无关和高衍射效率的 -1 阶超宽带三层介质传输矩形槽光栅。全介电光栅由放置在熔融石英衬底上的三层光栅脊组成。接下来，采用简化模式法分析衍射过程，并采用严格耦合分析和模拟退火算法计算出光栅结构的优化参数。对于 TE 和 TM 偏振，透射光栅的理论 -1 阶效率超过 95%，入射波长范围为 1446-1641 nm，入射角范围分别为 32.1-42.7。我们还讨论了取决于光栅周期和三个介电层厚度的大制造公差确保了设计光栅在制造过程中的高性能。由于具有超宽带、高效率和偏振无关的特性，所设计的矩形全介电光栅对于色散的最实际应用应该具有重要意义。