Sensor based on continuous domain bound state sub-wavelength grating runway type resonant cavity

The invention relates to a sensor based on a continuous domain bound state sub-wavelength grating runway type resonant cavity, which structurally comprises an intrinsic silicon substrate (1) as a first layer, a buried oxide layer (2) as a second layer, a silicon nitride film (3) as a third layer and a runway type resonant cavity (4) as a fourth layer from bottom to top in sequence, the runway type resonant cavity comprises a runway type micro-ring (4.1), a bus waveguide (4.2) and a grating coupler (4.3). On a waveguide supporting a continuous domain constraint mode, by designing parameters of a sub-wavelength grating structure with the period smaller than the optical wavelength and a runway type resonant cavity, high-quality-factor light-limited propagation is achieved, and the waveguide is further applied to a sensor. The invention has the advantages of high throughput, high detection sensitivity, high quality factor, simple structure, easiness in manufacturing and the like, and can provide a solution for ra