Chen Ying, Zhao Zhiyong, Tian Yaning, Liu Xiaofei, Zhu Qiguang, Zhai Yingjian, Li Shaohua. Refractive Index Sensing Mechanism of Waveguide Coupled Gratings Nano-Heterostructure Containing Porous Silicon Layers[J]. Chinese Journal of Lasers, 2017, 44(10): 1010003