Integrated High-Contrast-Grating Optical Sensor Using Guided Mode

In finite-size high-contrast gratings (HCGs) guided modes with low Q values can occur. On the one hand, this is a resonant mode with a Q value of some hundreds only, on the other hand it can transform part of the finite-size incident wave into the in-plane direction. Such finite-size HCGs with guided modes are proposed here for optical sensors with an on-chip integrated p-i-n photodiode in the same HCG layer. The mode characteristics of the guided mode and the performance of the proposed integrated HCG-based optical sensors are investigated. The proposed integrated HCG-based optical sensors are compact, cost-effective, label-free, and highly sensitive, and can be extended to an array format increasing the throughput.