基于亚波长金属介质膜光栅的宽光谱消色差相位延迟器

Broadband Achromatic Phase Retarder Based on Subwavelength Metal Dielectric Gratings

消色差相位延迟器可以在较宽光谱范围内获得所需要的相位延迟量,是偏振光调制的核心元件之一。根据严格耦合波理论和遗传算法,提出了一种基于夹层式亚波长金属介质膜光栅的宽光谱消色差相位延迟器的设计方法,并设计了一种在900~1200nm波长范围内实现消色差的相位延迟器,其相位延迟量在90°左右的最大偏差小于2.3%,且横电波和横磁波的衍射效率均高于90%。数值分析表明,所设计的消色差相位延迟器对槽深和入射角具有较大的工艺容差。该消色差相位延迟器设计简单,性能稳定,具有重要的应用价值。

An achromatic phase retarder can obtain the desired phase retardation in a wide spectral range, and it is one of the core elements used in polarization light modulation. A design method for broadband achromatic phase retarder is proposed based on sandwich-type subwavelength metal dielectric gratings according to the rigorous coupled wave theory and the genetic algorithm. A phase retarder which can achieve achromatism is designed in the wavelength range of 900~1200 nm. The maximum deviation of phase retardation around 90° is less than 2.3%, and the diffraction efficiencies of transverse electric wave and transverse magnetic wave are both higher than 90%. The numerical analysis shows that the designed achromatic phase retarder has a large manufacture tolerance for groove depth and incidence angle. The achromatic phase retarder is simple in design, stable in performance and has an important application value.