具有特定滤波特性的防伪用亚微米光栅的设计和制作

Design and fabrication of sub-micron grating with given filter character for anti-counterfeiting

用于防伪技术的亚微米光栅的重要特性是在可见光范围内其零级衍射效率的滤波特性随着入射光的入射方位角(入射面与光栅槽的夹角)改变而改变,零级衍射效率曲线的中心波长发生移动。利用严格的耦合波理论分析计算其衍射效率特性,由所需要的衍射效率特性设计光栅参量,通过精细加工制作工艺,制造出周期为416 nm的亚微米光栅,其零级衍射效率的峰值波长的测量值在入射光零度方位角入射时为466 nm,90°方位角入射时为627 nm,与计算结果一致,由此完成具有特定滤波特性的防伪用亚微米光栅的设计和制作。

The important character of the sub-micron grating used for anti-counterfeiting is that its zero-diffraction efficiency has a filter character changing with the azimuth of the incident light in the visible spectrum range. This paper analyzes and calculates the zero-diffraction efficiency with the rigorous coupled-wave theory, designs the parameters of the grating with the needed filter character. The sub-micron grating used for anti-counterfeiting with wanted filter character was designed and fabricated using subtly manufacture process. The period of the grating is 416 nm. Measurement result indicates that the grating has a peak wavelength of 466 nm when the azimuth is zero and 627 nm when the azimuth is 90 degree. This result is consistent with that of the design calculation.