Design of Simultaneous Refractive Index Sensor Across Multi-Photonic Bandgaps Using Tamm Plasmon Modes

In this work, a refractive index sensor based on Tamm plasmons mode is proposed, capable of concurrent functionality across multiple photonic bandgaps. The proposed sensor structure consists of an analyte cavity sandwiched between a one-dimensional photonic crystal of SiO₂/TiO₂ and a thin metal film. Multiple photonic bandgaps are observed in multilayer structures composed of SiO₂/TiO₂ layers, each with a thickness of 150 nm. Tamm plasmon resonances have been demonstrated in various photonic bandgaps, enabling the detection of subtle changes in refractive index within the cavity region. Simulation studies utilizing the transfer matrix method (TMM) have been conducted to evaluate the performance of the proposed design. Several sensor metrics including sensitivity, full width at half-maximum, quality factor, and detection accuracy were assessed for evaluating sensor performance. The functioning principle of this optical sensor relies on altering the refractive index of the analyte, resulting in a shift in either the transmission or reflection spectrum. The study reveals that the resonance wavelength demonstrates a linear variation with the change in the analyte’s refractive index. The results demonstrate that the one-dimensional photonic crystal sensor based on multiple Tamm plasmons exhibits high quality factor and enhanced detection accuracy and is well-suited for detecting minute changes in analyte refractive index. Tamm resonance-based sensors, notable for their main advantage of prism-free coupling, offer a compelling alternative to other optical sensors like surface plasmon resonance-based sensors.