A narrowband retroreflection is demonstrated by using a cavity-resonator-integrated guided-mode resonance filter (CRIGF) integrated on a high-reflection substrate for an oblique incidence. A CRIGF consists of a thin-film waveguide and three parts of surface-relief gratings. The middle part of the grating acts as a grating coupler, and both side parts act as distributed Bragg reflectors constructing a waveguide resonator. A CRIGF of 20- $\mu \text{m}$ aperture on a multilayer dielectric mirror is designed and fabricated for the incidence angle of 9° and the operation wavelength of 1540 nm. A narrowband retroreflection of >85% efficiency with 2-nm bandwidth is obtained experimentally.

中文翻译：

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基于波导光栅结构的薄膜窄带后向反射器

通过使用集成在高反射基板上的腔谐振器集成导模谐振滤波器 (CRIGF) 进行斜入射，演示了窄带回射。CRIGF 由薄膜波导和三部分表面浮雕光栅组成。光栅的中间部分用作光栅耦合器，两侧部分用作构成波导谐振器的分布式布拉格反射器。设计和制造了一个 20-$\mu\text{m}$ 孔径的多层介质镜 CRIGF，入射角为 9°，工作波长为 1540 nm。通过实验获得了具有 2 nm 带宽的 >85% 效率的窄带回射。