Surface-enhanced Raman scattering sensor based on hybrid deep slot waveguide on an integrated photonic platform

We design and numerically study the surface-enhanced Raman scattering (SERS) sensor on an integrated photonic platform. The sensor, based on a hybrid deep slot waveguide, is formed by combining a metallic slot waveguide and a dielectric slot waveguide that has a groove under the slot. The mode coupling and conversion processes in the hybrid deep slot waveguide are demonstrated. The normalized volume enhancement factor (NVEF) based on |E|4 approximation is proposed to characterize the influences of the geometrical parameters on this sensor. The NVEF of the optimized sensor reaches 142.36 at the wavelength of 785 nm, indicating that the electric field in the entire metallic slot can be greatly strengthened. Simulation results show that such a hybrid deep slot waveguide can be utilized for field enhancement, rendering an application of SERS. Moreover, the integration of the proposed sensor with a microlaser and a microdemultiplexer, could realize an all-integrated on-chip SERS-based detection system instead of traditional free-space-based detection strategies.