Design of a Slot Photonic Crystal Waveguide for Highly Sensitive Evanescent Field Absorption Sensing in Fluids
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The 4th Conference on MicroFluidic Handling Systems (MFHS 2019).
The design of a highly sensitive sensor based on slot photonic crystal waveguide (slot-PCWG) is presented. These types of waveguides feature a hexagonal array of holes in a silicon slab, which are filled with SiO2. The waveguide is formed by removing elements from the regular photonic crystal grid in a row and embedding a slot in the center position. This concept allows a vast enhancement of the evanescent field ratio leading to a strong overlap between the field of the waveguide mode and the analyte. In the present work, we show that the sensitivity at constant slab thickness and waveguide-length of the slot-PCWG modes is greatly enhanced up to a factor of 7.6 compared to corresponding PCWGs modes or Si slab WGs.