Narrowband and Full-Angle Refractive Index Sensor Based on a Planar Multilayer Structure

This paper reports a design of a narrowband and full-angle refractive index sensor based on Tamm plasmon resonance by introducing a distributed Bragg reflector (DBR) integrated with a non-adjacent metal layer. The analyte flows into the cavity comprising of the DBR and the non-adjacent metal layer. Simulated results show that the incident light can be strongly confined in the specially designed cavity. The sharp reflection dip within the forbidden band of the isolated DBR indicates the excitation of Tamm mode, and the spectral characteristics were monitored upon exposure to various analytes with different refractive indices. The optimally designed system shows the sensitivity (S) and full width at half-maximum can be up to 860 nm/refractive index unit and ~2.2 nm with a figure of merit of 391. Furthermore, the highly-sensitive characteristic can be sustained in a wide angle range of 0° to almost 90° under both TM- and TE-polarized lights.