入射角调谐的三基色导模共振滤光片

Guided-Mode Resonance Filter for Three Primary Color Tuned by Incident Angle

介绍一种入射角调谐红绿蓝三基色导模共振滤光片(GMRF)的实现方法。利用严格耦合波理论(RCWA)分析入射角对导模共振滤光片反射光谱的影响,用TM偏振波在斜入射下得到两个不同位置的共振峰,通过调节入射角,使两个共振峰分别落在可见光波段和红外波段,并通过调整角度实现对可将光波段滤波波长的调谐。通过对参数的优化、调整,设计并制作了周期为544 nm的红、绿、蓝三基色导模共振彩色滤光片,结果显示该结构在26.8°、39.6°、46.0°入射角得到了良好的红、绿、蓝三基色,效率均在80%左右,半峰全宽约为5 nm。当其作为蓝、绿两色滤光片工作时,与传统亚波长导模共振结构相比,其周期相对较长,从而大大降低光栅制作难度。实验结果实现导模共振结构在彩色滤光片方面的应用,并对大周期导模共振器件的制作提供了积极的指导。

A method of designing guided-mode resonance filter （GMRF） for three-primary-color is proposed under oblique incidence. The effects of incident angle on the guided-mode resonance filter reflection spectrum are investigated with the method of rigorous coupled wave analysis （RCWA）. A single resonance splits into two formants under oblique incidence by TM-polarized light. By adjusting incident angle, one resonance wavelength is located in visible wavelength range, and the other one falls inside the infrared spectrum and the wavelength of the visible light can be tuned by incident angle. A 544 nm grating period guided-mode resonance filter is designed and fabricated for three-primary-color by adjusting and optimizing the parameters of the device. The fabricated filter exhibits blue, green and red color responsed at incident angles of 26.8° ,39.6° ,46.0° and it has a bandwidth of 5 nm with efficiency near 80%. Besides, when it works as blue and green color filter, it has a larger period compared with traditional sub-wavelength structure and greatly reduces the cost of grating fabrication. The experimental result promotes the application of guided-mode resonance structure in color filters and it has active guidance meaning for the fabrication of large-period guided-mode resonance device.