藉由改變金二元光柵的寬度及厚度探討繞射效率

Abstract

奈米結構下次波長的二元光柵因為具有控制光的繞射強度特性，因此吸引了很多人的關注與研究。我們的二元光柵是由12個不同寬度的光柵分別在12個單位週期下所組成，每個單位週期為240奈米，總週期為2880 奈米，光柵的共振波長可藉由調控光柵的厚度來改變，此外也能藉由改變光柵的厚度與寬度來最佳化繞射效率。本篇是採用正向入射並研究穿透光的繞射情況，從二元光柵的異常繞射的結果可以知道此結構能運作在可見光到紅外光波段。

Planar photonics with binary grating draws immense attention because of characteristics that allow for controlling the flow of light beyond that offered by natural material. Binary gratings are gratings of various widths in the 2880 nm period. The grating’s resonance wavelength is tunable by changing the thickness of the binary grating. This also allows for an optimized efficiency of diffraction. In addition, normal incidence with the transmission-type binary grating is discussed. Based on the anomalous refraction results, it is possible to realize binary grating devices with optimized dimensions in the visible to near-infrared (NIR) wavelength region.